[{"data":1,"prerenderedAt":6726},["ShallowReactive",2],{"lang-switch-post-\u002Fplaylists\u002Fmachine-learning-specialization\u002Flab02-model-representation":3,"post-pt-machine-learning-specialization-lab02-model-representation":4},"\u002Fen\u002Fplaylists\u002Fmachine-learning-specialization\u002Flab02-model-representation",{"id":5,"title":6,"body":7,"cover":6711,"date":6712,"description":6713,"extension":6714,"meta":6715,"navigation":2393,"order":2355,"path":6716,"playlist":6717,"seo":6718,"status":6719,"stem":6720,"tags":6721,"__hash__":6725},"posts\u002Fpt\u002Fplaylists\u002Fmachine-learning-specialization\u002Flab02-model-representation.md","Lab Opcional: Representação do Modelo",{"type":8,"value":9,"toc":6687},"minimark",[10,22,29,37,40,256,261,461,476,480,483,1173,1176,1582,1586,1605,1608,1820,2264,2328,2338,2343,2424,2439,2454,2473,2505,2548,2619,2623,2630,2957,2986,2995,3076,3080,3083,3091,3094,3098,3345,3359,3511,3618,3736,3812,3816,3826,3922,3932,3936,4004,4115,4118,4325,4332,5206,5270,5455,5459,5565,5620,5811,5817,5859,5868,5929,5933,6245,6248,6333,6453,6457,6467,6471,6508,6527,6533,6537,6540,6543,6546,6607,6610,6613,6620,6624,6671,6680,6683],[11,12,13],"blockquote",{},[14,15,16,17,21],"p",{},"Baseado no Lab Opcional 02 (Semana 1, Curso 1) da ",[18,19,20],"strong",{},"Machine Learning Specialization",", do Andrew Ng (DeepLearning.AI \u002F Stanford). Mas esquece o notebook por um segundo, bora entender o que tá rolando de verdade.",[14,23,24],{},[25,26],"img",{"alt":27,"src":28},"Meme \"IQ bell curve\" comparando regressão linear e deep learning: tanto quem tem pouco conhecimento quanto quem manja muito preferem regressão linear, só quem tá no meio do caminho acha deep learning mais chique","\u002Fimages\u002Fposts\u002Fmachine-learning-specialization\u002Flab02-model-representation\u002Fmeme-regressao-linear.jpg",[14,30,31,32,36],{},"Cola aqui: todo mundo que começa em ML ouve falar de rede neural, transformer, LLM, essas coisas todas cheias de hype. E aí abre o primeiro lab do curso mais recomendado da área e encontra... uma reta. ",[33,34,35],"code",{},"y = ax + b"," do ensino médio, só que com nome trocado.",[14,38,39],{},"Isso não é o curso \"enrolando\" antes de chegar no assunto de verdade. É o assunto de verdade. Regressão linear é o Lego básico: todo modelo mais chique que você for estudar depois (rede neural, regressão logística, sei lá o que vier) é, no fundo, um monte desses Legos empilhados. Entender esse aqui até o osso me ensinou muito mais do que decorar fórmula de rede neural sem saber de onde ela vem.",[14,41,42],{},[43,44,47,112],"span",{"className":45},[46],"katex",[43,48,51],{"className":49},[50],"katex-mathml",[52,53,55],"math",{"xmlns":54},"http:\u002F\u002Fwww.w3.org\u002F1998\u002FMath\u002FMathML",[56,57,58,107],"semantics",{},[59,60,61,81,85,88,91,94,96,100,102,105],"mrow",{},[62,63,64,68],"msub",{},[65,66,67],"mi",{},"f",[59,69,70,73,78],{},[65,71,72],{},"w",[74,75,77],"mo",{"separator":76},"true",",",[65,79,80],{},"b",[74,82,84],{"stretchy":83},"false","(",[65,86,87],{},"x",[74,89,90],{"stretchy":83},")",[74,92,93],{},"=",[65,95,72],{},[97,98,99],"mtext",{}," ",[65,101,87],{},[74,103,104],{},"+",[65,106,80],{},[108,109,111],"annotation",{"encoding":110},"application\u002Fx-tex","f_{w,b}(x) = w\\,x + b",[43,113,116,218,246],{"className":114,"ariaHidden":76},[115],"katex-html",[43,117,120,125,195,199,202,206,211,215],{"className":118},[119],"base",[43,121],{"className":122,"style":124},[123],"strut","height:1.0361em;vertical-align:-0.2861em;",[43,126,129,134],{"className":127},[128],"mord",[43,130,67],{"className":131,"style":133},[128,132],"mathnormal","margin-right:0.1076em;",[43,135,138],{"className":136},[137],"msupsub",[43,139,143,186],{"className":140},[141,142],"vlist-t","vlist-t2",[43,144,147,181],{"className":145},[146],"vlist-r",[43,148,152],{"className":149,"style":151},[150],"vlist","height:0.3361em;",[43,153,155,160],{"style":154},"top:-2.55em;margin-left:-0.1076em;margin-right:0.05em;",[43,156],{"className":157,"style":159},[158],"pstrut","height:2.7em;",[43,161,167],{"className":162},[163,164,165,166],"sizing","reset-size6","size3","mtight",[43,168,170,174,178],{"className":169},[128,166],[43,171,72],{"className":172,"style":173},[128,132,166],"margin-right:0.0269em;",[43,175,77],{"className":176},[177,166],"mpunct",[43,179,80],{"className":180},[128,132,166],[43,182,185],{"className":183},[184],"vlist-s","​",[43,187,189],{"className":188},[146],[43,190,193],{"className":191,"style":192},[150],"height:0.2861em;",[43,194],{},[43,196,84],{"className":197},[198],"mopen",[43,200,87],{"className":201},[128,132],[43,203,90],{"className":204},[205],"mclose",[43,207],{"className":208,"style":210},[209],"mspace","margin-right:0.2778em;",[43,212,93],{"className":213},[214],"mrel",[43,216],{"className":217,"style":210},[209],[43,219,221,225,228,232,235,239,243],{"className":220},[119],[43,222],{"className":223,"style":224},[123],"height:0.6667em;vertical-align:-0.0833em;",[43,226,72],{"className":227,"style":173},[128,132],[43,229],{"className":230,"style":231},[209],"margin-right:0.1667em;",[43,233,87],{"className":234},[128,132],[43,236],{"className":237,"style":238},[209],"margin-right:0.2222em;",[43,240,104],{"className":241},[242],"mbin",[43,244],{"className":245,"style":238},[209],[43,247,249,253],{"className":248},[119],[43,250],{"className":251,"style":252},[123],"height:0.6944em;",[43,254,80],{"className":255},[128,132],[257,258,260],"h2",{"id":259},"o-que-você-vai-sair-sabendo-daqui","O que você vai sair sabendo daqui",[262,263,264,268,302,305,458],"ol",{},[265,266,267],"li",{},"Por que a gente representa dado de treino como array NumPy, e não lista Python.",[265,269,270,271,301],{},"Contar quantos exemplos de treino você tem (",[43,272,274,288],{"className":273},[46],[43,275,277],{"className":276},[50],[52,278,279],{"xmlns":54},[56,280,281,286],{},[59,282,283],{},[65,284,285],{},"m",[108,287,285],{"encoding":110},[43,289,291],{"className":290,"ariaHidden":76},[115],[43,292,294,298],{"className":293},[119],[43,295],{"className":296,"style":297},[123],"height:0.4306em;",[43,299,285],{"className":300},[128,132],") e pescar um exemplo específico.",[265,303,304],{},"Olhar pros dados antes de sair modelando (isso não é enrolação, é regra de ouro).",[265,306,307,308,457],{},"Montar o modelo ",[43,309,311,351],{"className":310},[46],[43,312,314],{"className":313},[50],[52,315,316],{"xmlns":54},[56,317,318,348],{},[59,319,320,332,334,336,338,340,342,344,346],{},[62,321,322,324],{},[65,323,67],{},[59,325,326,328,330],{},[65,327,72],{},[74,329,77],{"separator":76},[65,331,80],{},[74,333,84],{"stretchy":83},[65,335,87],{},[74,337,90],{"stretchy":83},[74,339,93],{},[65,341,72],{},[65,343,87],{},[74,345,104],{},[65,347,80],{},[108,349,350],{"encoding":110},"f_{w,b}(x) = wx + b",[43,352,354,427,448],{"className":353,"ariaHidden":76},[115],[43,355,357,360,409,412,415,418,421,424],{"className":356},[119],[43,358],{"className":359,"style":124},[123],[43,361,363,366],{"className":362},[128],[43,364,67],{"className":365,"style":133},[128,132],[43,367,369],{"className":368},[137],[43,370,372,401],{"className":371},[141,142],[43,373,375,398],{"className":374},[146],[43,376,378],{"className":377,"style":151},[150],[43,379,380,383],{"style":154},[43,381],{"className":382,"style":159},[158],[43,384,386],{"className":385},[163,164,165,166],[43,387,389,392,395],{"className":388},[128,166],[43,390,72],{"className":391,"style":173},[128,132,166],[43,393,77],{"className":394},[177,166],[43,396,80],{"className":397},[128,132,166],[43,399,185],{"className":400},[184],[43,402,404],{"className":403},[146],[43,405,407],{"className":406,"style":192},[150],[43,408],{},[43,410,84],{"className":411},[198],[43,413,87],{"className":414},[128,132],[43,416,90],{"className":417},[205],[43,419],{"className":420,"style":210},[209],[43,422,93],{"className":423},[214],[43,425],{"className":426,"style":210},[209],[43,428,430,433,436,439,442,445],{"className":429},[119],[43,431],{"className":432,"style":224},[123],[43,434,72],{"className":435,"style":173},[128,132],[43,437,87],{"className":438},[128,132],[43,440],{"className":441,"style":238},[209],[43,443,104],{"className":444},[242],[43,446],{"className":447,"style":238},[209],[43,449,451,454],{"className":450},[119],[43,452],{"className":453,"style":252},[123],[43,455,80],{"className":456},[128,132]," em código.",[265,459,460],{},"Brincar com os parâmetros até achar o ajuste perfeito, na mão, sem fórmula mágica, e sentir na pele por que isso não escala.",[14,462,463,464,467,468,471,472,475],{},"Todo modelo supervisionado tem três peças: ",[18,465,466],{},"os dados",", ",[18,469,470],{},"a função do modelo"," e ",[18,473,474],{},"os parâmetros",". Esse post monta as três peças na versão mais simples que existe. Guarda essa estrutura: ela reaparece, só que maior, em praticamente tudo que vem depois no curso.",[257,477,479],{"id":478},"o-dicionário-da-área","O dicionário da área",[14,481,482],{},"ML tem um vício chato: adora inventar símbolo pra coisa simples. Aqui vai o \"dicionário\" que o curso usa, porque ele reaparece do início ao fim:",[484,485,486,503],"table",{},[487,488,489],"thead",{},[490,491,492,497,500],"tr",{},[493,494,496],"th",{"align":495},"left","Notação",[493,498,499],{"align":495},"O que é",[493,501,502],{"align":495},"Em Python",[504,505,506,546,587,628,672,870,909,948,987],"tbody",{},[490,507,508,540,543],{},[509,510,511],"td",{"align":495},[43,512,514,528],{"className":513},[46],[43,515,517],{"className":516},[50],[52,518,519],{"xmlns":54},[56,520,521,526],{},[59,522,523],{},[65,524,525],{},"a",[108,527,525],{"encoding":110},[43,529,531],{"className":530,"ariaHidden":76},[115],[43,532,534,537],{"className":533},[119],[43,535],{"className":536,"style":297},[123],[43,538,525],{"className":539},[128,132],[509,541,542],{"align":495},"um número solto (escalar)",[509,544,545],{"align":495},"-",[490,547,548,582,585],{},[509,549,550],{"align":495},[43,551,553,568],{"className":552},[46],[43,554,556],{"className":555},[50],[52,557,558],{"xmlns":54},[56,559,560,565],{},[59,561,562],{},[65,563,525],{"mathvariant":564},"bold",[108,566,567],{"encoding":110},"\\mathbf{a}",[43,569,571],{"className":570,"ariaHidden":76},[115],[43,572,574,578],{"className":573},[119],[43,575],{"className":576,"style":577},[123],"height:0.4444em;",[43,579,525],{"className":580},[128,581],"mathbf",[509,583,584],{"align":495},"uma lista de números (vetor, letra em negrito)",[509,586,545],{"align":495},[490,588,589,620,623],{},[509,590,591],{"align":495},[43,592,594,608],{"className":593},[46],[43,595,597],{"className":596},[50],[52,598,599],{"xmlns":54},[56,600,601,605],{},[59,602,603],{},[65,604,87],{"mathvariant":564},[108,606,607],{"encoding":110},"\\mathbf{x}",[43,609,611],{"className":610,"ariaHidden":76},[115],[43,612,614,617],{"className":613},[119],[43,615],{"className":616,"style":577},[123],[43,618,87],{"className":619},[128,581],[509,621,622],{"align":495},"os valores de entrada de todos os exemplos de treino",[509,624,625],{"align":495},[33,626,627],{},"x_train",[490,629,630,664,667],{},[509,631,632],{"align":495},[43,633,635,650],{"className":634},[46],[43,636,638],{"className":637},[50],[52,639,640],{"xmlns":54},[56,641,642,647],{},[59,643,644],{},[65,645,646],{"mathvariant":564},"y",[108,648,649],{"encoding":110},"\\mathbf{y}",[43,651,653],{"className":652,"ariaHidden":76},[115],[43,654,656,660],{"className":655},[119],[43,657],{"className":658,"style":659},[123],"height:0.6389em;vertical-align:-0.1944em;",[43,661,646],{"className":662,"style":663},[128,581],"margin-right:0.016em;",[509,665,666],{"align":495},"os valores que a gente quer prever, de todos os exemplos",[509,668,669],{"align":495},[33,670,671],{},"y_train",[490,673,674,830,862],{},[509,675,676,467,754],{"align":495},[43,677,679,705],{"className":678},[46],[43,680,682],{"className":681},[50],[52,683,684],{"xmlns":54},[56,685,686,702],{},[59,687,688],{},[689,690,691,693],"msup",{},[65,692,87],{},[59,694,695,697,700],{},[74,696,84],{"stretchy":83},[65,698,699],{},"i",[74,701,90],{"stretchy":83},[108,703,704],{"encoding":110},"x^{(i)}",[43,706,708],{"className":707,"ariaHidden":76},[115],[43,709,711,715],{"className":710},[119],[43,712],{"className":713,"style":714},[123],"height:0.888em;",[43,716,718,721],{"className":717},[128],[43,719,87],{"className":720},[128,132],[43,722,724],{"className":723},[137],[43,725,727],{"className":726},[141],[43,728,730],{"className":729},[146],[43,731,733],{"className":732,"style":714},[150],[43,734,736,739],{"style":735},"top:-3.063em;margin-right:0.05em;",[43,737],{"className":738,"style":159},[158],[43,740,742],{"className":741},[163,164,165,166],[43,743,745,748,751],{"className":744},[128,166],[43,746,84],{"className":747},[198,166],[43,749,699],{"className":750},[128,132,166],[43,752,90],{"className":753},[205,166],[43,755,757,781],{"className":756},[46],[43,758,760],{"className":759},[50],[52,761,762],{"xmlns":54},[56,763,764,778],{},[59,765,766],{},[689,767,768,770],{},[65,769,646],{},[59,771,772,774,776],{},[74,773,84],{"stretchy":83},[65,775,699],{},[74,777,90],{"stretchy":83},[108,779,780],{"encoding":110},"y^{(i)}",[43,782,784],{"className":783,"ariaHidden":76},[115],[43,785,787,791],{"className":786},[119],[43,788],{"className":789,"style":790},[123],"height:1.0824em;vertical-align:-0.1944em;",[43,792,794,798],{"className":793},[128],[43,795,646],{"className":796,"style":797},[128,132],"margin-right:0.0359em;",[43,799,801],{"className":800},[137],[43,802,804],{"className":803},[141],[43,805,807],{"className":806},[146],[43,808,810],{"className":809,"style":714},[150],[43,811,812,815],{"style":735},[43,813],{"className":814,"style":159},[158],[43,816,818],{"className":817},[163,164,165,166],[43,819,821,824,827],{"className":820},[128,166],[43,822,84],{"className":823},[198,166],[43,825,699],{"className":826},[128,132,166],[43,828,90],{"className":829},[205,166],[509,831,832,833],{"align":495},"o par de valores do exemplo número ",[43,834,836,849],{"className":835},[46],[43,837,839],{"className":838},[50],[52,840,841],{"xmlns":54},[56,842,843,847],{},[59,844,845],{},[65,846,699],{},[108,848,699],{"encoding":110},[43,850,852],{"className":851,"ariaHidden":76},[115],[43,853,855,859],{"className":854},[119],[43,856],{"className":857,"style":858},[123],"height:0.6595em;",[43,860,699],{"className":861},[128,132],[509,863,864,467,867],{"align":495},[33,865,866],{},"x_i",[33,868,869],{},"y_i",[490,871,872,902,905],{},[509,873,874],{"align":495},[43,875,877,890],{"className":876},[46],[43,878,880],{"className":879},[50],[52,881,882],{"xmlns":54},[56,883,884,888],{},[59,885,886],{},[65,887,285],{},[108,889,285],{"encoding":110},[43,891,893],{"className":892,"ariaHidden":76},[115],[43,894,896,899],{"className":895},[119],[43,897],{"className":898,"style":297},[123],[43,900,285],{"className":901},[128,132],[509,903,904],{"align":495},"quantos exemplos de treino você tem",[509,906,907],{"align":495},[33,908,285],{},[490,910,911,941,944],{},[509,912,913],{"align":495},[43,914,916,929],{"className":915},[46],[43,917,919],{"className":918},[50],[52,920,921],{"xmlns":54},[56,922,923,927],{},[59,924,925],{},[65,926,72],{},[108,928,72],{"encoding":110},[43,930,932],{"className":931,"ariaHidden":76},[115],[43,933,935,938],{"className":934},[119],[43,936],{"className":937,"style":297},[123],[43,939,72],{"className":940,"style":173},[128,132],[509,942,943],{"align":495},"peso (a inclinação da reta)",[509,945,946],{"align":495},[33,947,72],{},[490,949,950,980,983],{},[509,951,952],{"align":495},[43,953,955,968],{"className":954},[46],[43,956,958],{"className":957},[50],[52,959,960],{"xmlns":54},[56,961,962,966],{},[59,963,964],{},[65,965,80],{},[108,967,80],{"encoding":110},[43,969,971],{"className":970,"ariaHidden":76},[115],[43,972,974,977],{"className":973},[119],[43,975],{"className":976,"style":252},[123],[43,978,80],{"className":979},[128,132],[509,981,982],{"align":495},"viés (o ponto de partida da reta)",[509,984,985],{"align":495},[33,986,80],{},[490,988,989,1137,1168],{},[509,990,991],{"align":495},[43,992,994,1034],{"className":993},[46],[43,995,997],{"className":996},[50],[52,998,999],{"xmlns":54},[56,1000,1001,1031],{},[59,1002,1003,1015,1017,1029],{},[62,1004,1005,1007],{},[65,1006,67],{},[59,1008,1009,1011,1013],{},[65,1010,72],{},[74,1012,77],{"separator":76},[65,1014,80],{},[74,1016,84],{"stretchy":83},[689,1018,1019,1021],{},[65,1020,87],{},[59,1022,1023,1025,1027],{},[74,1024,84],{"stretchy":83},[65,1026,699],{},[74,1028,90],{"stretchy":83},[74,1030,90],{"stretchy":83},[108,1032,1033],{"encoding":110},"f_{w,b}(x^{(i)})",[43,1035,1037],{"className":1036,"ariaHidden":76},[115],[43,1038,1040,1044,1093,1096,1134],{"className":1039},[119],[43,1041],{"className":1042,"style":1043},[123],"height:1.1741em;vertical-align:-0.2861em;",[43,1045,1047,1050],{"className":1046},[128],[43,1048,67],{"className":1049,"style":133},[128,132],[43,1051,1053],{"className":1052},[137],[43,1054,1056,1085],{"className":1055},[141,142],[43,1057,1059,1082],{"className":1058},[146],[43,1060,1062],{"className":1061,"style":151},[150],[43,1063,1064,1067],{"style":154},[43,1065],{"className":1066,"style":159},[158],[43,1068,1070],{"className":1069},[163,164,165,166],[43,1071,1073,1076,1079],{"className":1072},[128,166],[43,1074,72],{"className":1075,"style":173},[128,132,166],[43,1077,77],{"className":1078},[177,166],[43,1080,80],{"className":1081},[128,132,166],[43,1083,185],{"className":1084},[184],[43,1086,1088],{"className":1087},[146],[43,1089,1091],{"className":1090,"style":192},[150],[43,1092],{},[43,1094,84],{"className":1095},[198],[43,1097,1099,1102],{"className":1098},[128],[43,1100,87],{"className":1101},[128,132],[43,1103,1105],{"className":1104},[137],[43,1106,1108],{"className":1107},[141],[43,1109,1111],{"className":1110},[146],[43,1112,1114],{"className":1113,"style":714},[150],[43,1115,1116,1119],{"style":735},[43,1117],{"className":1118,"style":159},[158],[43,1120,1122],{"className":1121},[163,164,165,166],[43,1123,1125,1128,1131],{"className":1124},[128,166],[43,1126,84],{"className":1127},[198,166],[43,1129,699],{"className":1130},[128,132,166],[43,1132,90],{"className":1133},[205,166],[43,1135,90],{"className":1136},[205],[509,1138,1139,1140],{"align":495},"o que o modelo prevê pro exemplo ",[43,1141,1143,1156],{"className":1142},[46],[43,1144,1146],{"className":1145},[50],[52,1147,1148],{"xmlns":54},[56,1149,1150,1154],{},[59,1151,1152],{},[65,1153,699],{},[108,1155,699],{"encoding":110},[43,1157,1159],{"className":1158,"ariaHidden":76},[115],[43,1160,1162,1165],{"className":1161},[119],[43,1163],{"className":1164,"style":858},[123],[43,1166,699],{"className":1167},[128,132],[509,1169,1170],{"align":495},[33,1171,1172],{},"f_wb",[14,1174,1175],{},"Duas pegadinhas que confundem todo iniciante:",[1177,1178,1179,1401],"ul",{},[265,1180,1181,1254,1255,1258,1259,1262,1263,1339,1340,1400],{},[43,1182,1184,1207],{"className":1183},[46],[43,1185,1187],{"className":1186},[50],[52,1188,1189],{"xmlns":54},[56,1190,1191,1205],{},[59,1192,1193],{},[689,1194,1195,1197],{},[65,1196,87],{},[59,1198,1199,1201,1203],{},[74,1200,84],{"stretchy":83},[65,1202,699],{},[74,1204,90],{"stretchy":83},[108,1206,704],{"encoding":110},[43,1208,1210],{"className":1209,"ariaHidden":76},[115],[43,1211,1213,1216],{"className":1212},[119],[43,1214],{"className":1215,"style":714},[123],[43,1217,1219,1222],{"className":1218},[128],[43,1220,87],{"className":1221},[128,132],[43,1223,1225],{"className":1224},[137],[43,1226,1228],{"className":1227},[141],[43,1229,1231],{"className":1230},[146],[43,1232,1234],{"className":1233,"style":714},[150],[43,1235,1236,1239],{"style":735},[43,1237],{"className":1238,"style":159},[158],[43,1240,1242],{"className":1241},[163,164,165,166],[43,1243,1245,1248,1251],{"className":1244},[128,166],[43,1246,84],{"className":1247},[198,166],[43,1249,699],{"className":1250},[128,132,166],[43,1252,90],{"className":1253},[205,166]," ",[18,1256,1257],{},"não é"," potência. O ",[33,1260,1261],{},"(i)"," entre parênteses é só \"qual exemplo da tabela\", tipo o número da linha. ",[43,1264,1266,1292],{"className":1265},[46],[43,1267,1269],{"className":1268},[50],[52,1270,1271],{"xmlns":54},[56,1272,1273,1289],{},[59,1274,1275],{},[689,1276,1277,1279],{},[65,1278,87],{},[59,1280,1281,1283,1287],{},[74,1282,84],{"stretchy":83},[1284,1285,1286],"mn",{},"2",[74,1288,90],{"stretchy":83},[108,1290,1291],{"encoding":110},"x^{(2)}",[43,1293,1295],{"className":1294,"ariaHidden":76},[115],[43,1296,1298,1301],{"className":1297},[119],[43,1299],{"className":1300,"style":714},[123],[43,1302,1304,1307],{"className":1303},[128],[43,1305,87],{"className":1306},[128,132],[43,1308,1310],{"className":1309},[137],[43,1311,1313],{"className":1312},[141],[43,1314,1316],{"className":1315},[146],[43,1317,1319],{"className":1318,"style":714},[150],[43,1320,1321,1324],{"style":735},[43,1322],{"className":1323,"style":159},[158],[43,1325,1327],{"className":1326},[163,164,165,166],[43,1328,1330,1333,1336],{"className":1329},[128,166],[43,1331,84],{"className":1332},[198,166],[43,1334,1286],{"className":1335},[128,166],[43,1337,90],{"className":1338},[205,166]," é o terceiro exemplo (lembra, começa do zero), enquanto ",[43,1341,1343,1361],{"className":1342},[46],[43,1344,1346],{"className":1345},[50],[52,1347,1348],{"xmlns":54},[56,1349,1350,1358],{},[59,1351,1352],{},[689,1353,1354,1356],{},[65,1355,87],{},[1284,1357,1286],{},[108,1359,1360],{"encoding":110},"x^2",[43,1362,1364],{"className":1363,"ariaHidden":76},[115],[43,1365,1367,1371],{"className":1366},[119],[43,1368],{"className":1369,"style":1370},[123],"height:0.8141em;",[43,1372,1374,1377],{"className":1373},[128],[43,1375,87],{"className":1376},[128,132],[43,1378,1380],{"className":1379},[137],[43,1381,1383],{"className":1382},[141],[43,1384,1386],{"className":1385},[146],[43,1387,1389],{"className":1388,"style":1370},[150],[43,1390,1391,1394],{"style":735},[43,1392],{"className":1393,"style":159},[158],[43,1395,1397],{"className":1396},[163,164,165,166],[43,1398,1286],{"className":1399},[128,166]," seria \"x ao quadrado\", coisa bem diferente.",[265,1402,1403,1431,1432,1435,1436,1465,1466,1469,1470,1498,1499,1527,1528,1581],{},[43,1404,1406,1419],{"className":1405},[46],[43,1407,1409],{"className":1408},[50],[52,1410,1411],{"xmlns":54},[56,1412,1413,1417],{},[59,1414,1415],{},[65,1416,285],{},[108,1418,285],{"encoding":110},[43,1420,1422],{"className":1421,"ariaHidden":76},[115],[43,1423,1425,1428],{"className":1424},[119],[43,1426],{"className":1427,"style":297},[123],[43,1429,285],{"className":1430},[128,132]," é número de ",[18,1433,1434],{},"linhas"," (exemplos). Mais pra frente aparece ",[43,1437,1439,1453],{"className":1438},[46],[43,1440,1442],{"className":1441},[50],[52,1443,1444],{"xmlns":54},[56,1445,1446,1451],{},[59,1447,1448],{},[65,1449,1450],{},"n",[108,1452,1450],{"encoding":110},[43,1454,1456],{"className":1455,"ariaHidden":76},[115],[43,1457,1459,1462],{"className":1458},[119],[43,1460],{"className":1461,"style":297},[123],[43,1463,1450],{"className":1464},[128,132],", número de ",[18,1467,1468],{},"colunas"," (features\u002Fatributos). Pensa numa planilha de Excel: ",[43,1471,1473,1486],{"className":1472},[46],[43,1474,1476],{"className":1475},[50],[52,1477,1478],{"xmlns":54},[56,1479,1480,1484],{},[59,1481,1482],{},[65,1483,285],{},[108,1485,285],{"encoding":110},[43,1487,1489],{"className":1488,"ariaHidden":76},[115],[43,1490,1492,1495],{"className":1491},[119],[43,1493],{"className":1494,"style":297},[123],[43,1496,285],{"className":1497},[128,132]," é quantas casas você tem cadastradas, ",[43,1500,1502,1515],{"className":1501},[46],[43,1503,1505],{"className":1504},[50],[52,1506,1507],{"xmlns":54},[56,1508,1509,1513],{},[59,1510,1511],{},[65,1512,1450],{},[108,1514,1450],{"encoding":110},[43,1516,1518],{"className":1517,"ariaHidden":76},[115],[43,1519,1521,1524],{"className":1520},[119],[43,1522],{"className":1523,"style":297},[123],[43,1525,1450],{"className":1526},[128,132]," é quantas colunas de informação você anotou sobre cada uma (tamanho, número de quartos, bairro...). Aqui a gente só tem uma coluna, então ",[43,1529,1531,1550],{"className":1530},[46],[43,1532,1534],{"className":1533},[50],[52,1535,1536],{"xmlns":54},[56,1537,1538,1547],{},[59,1539,1540,1542,1544],{},[65,1541,1450],{},[74,1543,93],{},[1284,1545,1546],{},"1",[108,1548,1549],{"encoding":110},"n = 1",[43,1551,1553,1571],{"className":1552,"ariaHidden":76},[115],[43,1554,1556,1559,1562,1565,1568],{"className":1555},[119],[43,1557],{"className":1558,"style":297},[123],[43,1560,1450],{"className":1561},[128,132],[43,1563],{"className":1564,"style":210},[209],[43,1566,93],{"className":1567},[214],[43,1569],{"className":1570,"style":210},[209],[43,1572,1574,1578],{"className":1573},[119],[43,1575],{"className":1576,"style":1577},[123],"height:0.6444em;",[43,1579,1546],{"className":1580},[128],".",[257,1583,1585],{"id":1584},"o-problema-quanto-vale-essa-casa-aí","O problema: quanto vale essa casa aí?",[14,1587,1588,1589,1592,1593,1596,1597,1600,1601,1604],{},"Cenário: você é corretor e só fechou duas vendas até agora. Uma casa de ",[18,1590,1591],{},"1000 pés²"," foi vendida por ",[18,1594,1595],{},"300 mil dólares",", e uma de ",[18,1598,1599],{},"2000 pés²",", por ",[18,1602,1603],{},"500 mil",". Aparece um cliente com uma casa de 1200 pés² perguntando quanto ela vale. Você não tem bola de cristal, mas tem dois pontos de referência, e foi surpreendente quanto eu consegui tirar disso.",[14,1606,1607],{},"Pra não ficar escrevendo zero pra caramba, tamanho vira \"milhares de pés²\" e preço vira \"milhares de dólares\":",[484,1609,1610,1797],{},[487,1611,1612],{},[490,1613,1614,1645,1721],{},[493,1615,1617],{"align":1616},"center",[43,1618,1620,1633],{"className":1619},[46],[43,1621,1623],{"className":1622},[50],[52,1624,1625],{"xmlns":54},[56,1626,1627,1631],{},[59,1628,1629],{},[65,1630,699],{},[108,1632,699],{"encoding":110},[43,1634,1636],{"className":1635,"ariaHidden":76},[115],[43,1637,1639,1642],{"className":1638},[119],[43,1640],{"className":1641,"style":858},[123],[43,1643,699],{"className":1644},[128,132],[493,1646,1647,1648],{"align":1616},"Tamanho (1000 pés²) → ",[43,1649,1651,1674],{"className":1650},[46],[43,1652,1654],{"className":1653},[50],[52,1655,1656],{"xmlns":54},[56,1657,1658,1672],{},[59,1659,1660],{},[689,1661,1662,1664],{},[65,1663,87],{},[59,1665,1666,1668,1670],{},[74,1667,84],{"stretchy":83},[65,1669,699],{},[74,1671,90],{"stretchy":83},[108,1673,704],{"encoding":110},[43,1675,1677],{"className":1676,"ariaHidden":76},[115],[43,1678,1680,1683],{"className":1679},[119],[43,1681],{"className":1682,"style":714},[123],[43,1684,1686,1689],{"className":1685},[128],[43,1687,87],{"className":1688},[128,132],[43,1690,1692],{"className":1691},[137],[43,1693,1695],{"className":1694},[141],[43,1696,1698],{"className":1697},[146],[43,1699,1701],{"className":1700,"style":714},[150],[43,1702,1703,1706],{"style":735},[43,1704],{"className":1705,"style":159},[158],[43,1707,1709],{"className":1708},[163,164,165,166],[43,1710,1712,1715,1718],{"className":1711},[128,166],[43,1713,84],{"className":1714},[198,166],[43,1716,699],{"className":1717},[128,132,166],[43,1719,90],{"className":1720},[205,166],[493,1722,1723,1724],{"align":1616},"Preço (1000 dólares) → ",[43,1725,1727,1750],{"className":1726},[46],[43,1728,1730],{"className":1729},[50],[52,1731,1732],{"xmlns":54},[56,1733,1734,1748],{},[59,1735,1736],{},[689,1737,1738,1740],{},[65,1739,646],{},[59,1741,1742,1744,1746],{},[74,1743,84],{"stretchy":83},[65,1745,699],{},[74,1747,90],{"stretchy":83},[108,1749,780],{"encoding":110},[43,1751,1753],{"className":1752,"ariaHidden":76},[115],[43,1754,1756,1759],{"className":1755},[119],[43,1757],{"className":1758,"style":790},[123],[43,1760,1762,1765],{"className":1761},[128],[43,1763,646],{"className":1764,"style":797},[128,132],[43,1766,1768],{"className":1767},[137],[43,1769,1771],{"className":1770},[141],[43,1772,1774],{"className":1773},[146],[43,1775,1777],{"className":1776,"style":714},[150],[43,1778,1779,1782],{"style":735},[43,1780],{"className":1781,"style":159},[158],[43,1783,1785],{"className":1784},[163,164,165,166],[43,1786,1788,1791,1794],{"className":1787},[128,166],[43,1789,84],{"className":1790},[198,166],[43,1792,699],{"className":1793},[128,132,166],[43,1795,90],{"className":1796},[205,166],[504,1798,1799,1810],{},[490,1800,1801,1804,1807],{},[509,1802,1803],{"align":1616},"0",[509,1805,1806],{"align":1616},"1.0",[509,1808,1809],{"align":1616},"300",[490,1811,1812,1814,1817],{},[509,1813,1546],{"align":1616},[509,1815,1816],{"align":1616},"2.0",[509,1818,1819],{"align":1616},"500",[14,1821,1822,1823,1874,1875,471,2071,1581],{},"Ou seja: ",[43,1824,1826,1844],{"className":1825},[46],[43,1827,1829],{"className":1828},[50],[52,1830,1831],{"xmlns":54},[56,1832,1833,1841],{},[59,1834,1835,1837,1839],{},[65,1836,285],{},[74,1838,93],{},[1284,1840,1286],{},[108,1842,1843],{"encoding":110},"m = 2",[43,1845,1847,1865],{"className":1846,"ariaHidden":76},[115],[43,1848,1850,1853,1856,1859,1862],{"className":1849},[119],[43,1851],{"className":1852,"style":297},[123],[43,1854,285],{"className":1855},[128,132],[43,1857],{"className":1858,"style":210},[209],[43,1860,93],{"className":1861},[214],[43,1863],{"className":1864,"style":210},[209],[43,1866,1868,1871],{"className":1867},[119],[43,1869],{"className":1870,"style":1577},[123],[43,1872,1286],{"className":1873},[128]," exemplos, ",[43,1876,1878,1936],{"className":1877},[46],[43,1879,1881],{"className":1880},[50],[52,1882,1883],{"xmlns":54},[56,1884,1885,1933],{},[59,1886,1887,1889,1901,1903,1915,1917,1919,1921,1923,1925,1928,1931],{},[74,1888,84],{"stretchy":83},[689,1890,1891,1893],{},[65,1892,87],{},[59,1894,1895,1897,1899],{},[74,1896,84],{"stretchy":83},[1284,1898,1803],{},[74,1900,90],{"stretchy":83},[74,1902,77],{"separator":76},[689,1904,1905,1907],{},[65,1906,646],{},[59,1908,1909,1911,1913],{},[74,1910,84],{"stretchy":83},[1284,1912,1803],{},[74,1914,90],{"stretchy":83},[74,1916,90],{"stretchy":83},[74,1918,93],{},[74,1920,84],{"stretchy":83},[1284,1922,1806],{},[74,1924,77],{"separator":76},[97,1926,1927],{}," ",[1284,1929,1930],{},"300.0",[74,1932,90],{"stretchy":83},[108,1934,1935],{"encoding":110},"(x^{(0)}, y^{(0)}) = (1.0,\\ 300.0)",[43,1937,1939,2043],{"className":1938,"ariaHidden":76},[115],[43,1940,1942,1946,1949,1987,1990,1993,2031,2034,2037,2040],{"className":1941},[119],[43,1943],{"className":1944,"style":1945},[123],"height:1.138em;vertical-align:-0.25em;",[43,1947,84],{"className":1948},[198],[43,1950,1952,1955],{"className":1951},[128],[43,1953,87],{"className":1954},[128,132],[43,1956,1958],{"className":1957},[137],[43,1959,1961],{"className":1960},[141],[43,1962,1964],{"className":1963},[146],[43,1965,1967],{"className":1966,"style":714},[150],[43,1968,1969,1972],{"style":735},[43,1970],{"className":1971,"style":159},[158],[43,1973,1975],{"className":1974},[163,164,165,166],[43,1976,1978,1981,1984],{"className":1977},[128,166],[43,1979,84],{"className":1980},[198,166],[43,1982,1803],{"className":1983},[128,166],[43,1985,90],{"className":1986},[205,166],[43,1988,77],{"className":1989},[177],[43,1991],{"className":1992,"style":231},[209],[43,1994,1996,1999],{"className":1995},[128],[43,1997,646],{"className":1998,"style":797},[128,132],[43,2000,2002],{"className":2001},[137],[43,2003,2005],{"className":2004},[141],[43,2006,2008],{"className":2007},[146],[43,2009,2011],{"className":2010,"style":714},[150],[43,2012,2013,2016],{"style":735},[43,2014],{"className":2015,"style":159},[158],[43,2017,2019],{"className":2018},[163,164,165,166],[43,2020,2022,2025,2028],{"className":2021},[128,166],[43,2023,84],{"className":2024},[198,166],[43,2026,1803],{"className":2027},[128,166],[43,2029,90],{"className":2030},[205,166],[43,2032,90],{"className":2033},[205],[43,2035],{"className":2036,"style":210},[209],[43,2038,93],{"className":2039},[214],[43,2041],{"className":2042,"style":210},[209],[43,2044,2046,2050,2053,2056,2059,2062,2065,2068],{"className":2045},[119],[43,2047],{"className":2048,"style":2049},[123],"height:1em;vertical-align:-0.25em;",[43,2051,84],{"className":2052},[198],[43,2054,1806],{"className":2055},[128],[43,2057,77],{"className":2058},[177],[43,2060,1927],{"className":2061},[209],[43,2063],{"className":2064,"style":231},[209],[43,2066,1930],{"className":2067},[128],[43,2069,90],{"className":2070},[205],[43,2072,2074,2131],{"className":2073},[46],[43,2075,2077],{"className":2076},[50],[52,2078,2079],{"xmlns":54},[56,2080,2081,2128],{},[59,2082,2083,2085,2097,2099,2111,2113,2115,2117,2119,2121,2123,2126],{},[74,2084,84],{"stretchy":83},[689,2086,2087,2089],{},[65,2088,87],{},[59,2090,2091,2093,2095],{},[74,2092,84],{"stretchy":83},[1284,2094,1546],{},[74,2096,90],{"stretchy":83},[74,2098,77],{"separator":76},[689,2100,2101,2103],{},[65,2102,646],{},[59,2104,2105,2107,2109],{},[74,2106,84],{"stretchy":83},[1284,2108,1546],{},[74,2110,90],{"stretchy":83},[74,2112,90],{"stretchy":83},[74,2114,93],{},[74,2116,84],{"stretchy":83},[1284,2118,1816],{},[74,2120,77],{"separator":76},[97,2122,1927],{},[1284,2124,2125],{},"500.0",[74,2127,90],{"stretchy":83},[108,2129,2130],{"encoding":110},"(x^{(1)}, y^{(1)}) = (2.0,\\ 500.0)",[43,2132,2134,2237],{"className":2133,"ariaHidden":76},[115],[43,2135,2137,2140,2143,2181,2184,2187,2225,2228,2231,2234],{"className":2136},[119],[43,2138],{"className":2139,"style":1945},[123],[43,2141,84],{"className":2142},[198],[43,2144,2146,2149],{"className":2145},[128],[43,2147,87],{"className":2148},[128,132],[43,2150,2152],{"className":2151},[137],[43,2153,2155],{"className":2154},[141],[43,2156,2158],{"className":2157},[146],[43,2159,2161],{"className":2160,"style":714},[150],[43,2162,2163,2166],{"style":735},[43,2164],{"className":2165,"style":159},[158],[43,2167,2169],{"className":2168},[163,164,165,166],[43,2170,2172,2175,2178],{"className":2171},[128,166],[43,2173,84],{"className":2174},[198,166],[43,2176,1546],{"className":2177},[128,166],[43,2179,90],{"className":2180},[205,166],[43,2182,77],{"className":2183},[177],[43,2185],{"className":2186,"style":231},[209],[43,2188,2190,2193],{"className":2189},[128],[43,2191,646],{"className":2192,"style":797},[128,132],[43,2194,2196],{"className":2195},[137],[43,2197,2199],{"className":2198},[141],[43,2200,2202],{"className":2201},[146],[43,2203,2205],{"className":2204,"style":714},[150],[43,2206,2207,2210],{"style":735},[43,2208],{"className":2209,"style":159},[158],[43,2211,2213],{"className":2212},[163,164,165,166],[43,2214,2216,2219,2222],{"className":2215},[128,166],[43,2217,84],{"className":2218},[198,166],[43,2220,1546],{"className":2221},[128,166],[43,2223,90],{"className":2224},[205,166],[43,2226,90],{"className":2227},[205],[43,2229],{"className":2230,"style":210},[209],[43,2232,93],{"className":2233},[214],[43,2235],{"className":2236,"style":210},[209],[43,2238,2240,2243,2246,2249,2252,2255,2258,2261],{"className":2239},[119],[43,2241],{"className":2242,"style":2049},[123],[43,2244,84],{"className":2245},[198],[43,2247,1816],{"className":2248},[128],[43,2250,77],{"className":2251},[177],[43,2253,1927],{"className":2254},[209],[43,2256],{"className":2257,"style":231},[209],[43,2259,2125],{"className":2260},[128],[43,2262,90],{"className":2263},[205],[14,2265,2266,2267,471,2295,2323,2324,2327],{},"Meu plano era achar uma reta que passasse (ou chegasse perto) desses pontos. Achando essa reta (ou seja, achando ",[43,2268,2270,2283],{"className":2269},[46],[43,2271,2273],{"className":2272},[50],[52,2274,2275],{"xmlns":54},[56,2276,2277,2281],{},[59,2278,2279],{},[65,2280,72],{},[108,2282,72],{"encoding":110},[43,2284,2286],{"className":2285,"ariaHidden":76},[115],[43,2287,2289,2292],{"className":2288},[119],[43,2290],{"className":2291,"style":297},[123],[43,2293,72],{"className":2294,"style":173},[128,132],[43,2296,2298,2311],{"className":2297},[46],[43,2299,2301],{"className":2300},[50],[52,2302,2303],{"xmlns":54},[56,2304,2305,2309],{},[59,2306,2307],{},[65,2308,80],{},[108,2310,80],{"encoding":110},[43,2312,2314],{"className":2313,"ariaHidden":76},[115],[43,2315,2317,2320],{"className":2316},[119],[43,2318],{"className":2319,"style":252},[123],[43,2321,80],{"className":2322},[128,132],") eu consigo estimar o preço de ",[18,2325,2326],{},"qualquer"," casa nova, incluindo uma que a gente nunca viu, tipo a de 1200 pés².",[11,2329,2330],{},[14,2331,2332,2333,2337],{},"Escala menor é hábito, não frescura: mais pra frente no curso, quando os números ficarem grandes de verdade (preço de casa em SP, tipo), normalizar as escalas (",[2334,2335,2336],"em",{},"feature scaling",") vai ser essencial pro treino nem travar nem enlouquecer. Já vai acostumando o olho.",[2339,2340,2342],"h3",{"id":2341},"bota-isso-num-array","Bota isso num array",[2344,2345,2350],"pre",{"className":2346,"code":2347,"language":2348,"meta":2349,"style":2349},"language-python shiki shiki-themes github-light github-dark","# =====================================================================\n# DADOS DE TREINO\n# =====================================================================\n# x_train -> variável de ENTRADA (feature): tamanho da casa, em milhares de pés²\n# y_train -> variável ALVO (target):        preço da casa, em milhares de dólares\n# A ordem importa: x_train[0] e y_train[0] descrevem a MESMA casa.\n\nx_train = np.array([1.0, 2.0])       # Cria um array NumPy 1-D com os dois tamanhos.\ny_train = np.array([300.0, 500.0])   # Cria um array NumPy 1-D com os dois preços correspondentes.\n\nprint(f\"x_train = {x_train}\")\nprint(f\"y_train = {y_train}\")\n","python","",[33,2351,2352,2359,2365,2370,2376,2382,2388,2395,2401,2407,2412,2418],{"__ignoreMap":2349},[43,2353,2356],{"class":2354,"line":2355},"line",1,[43,2357,2358],{},"# =====================================================================\n",[43,2360,2362],{"class":2354,"line":2361},2,[43,2363,2364],{},"# DADOS DE TREINO\n",[43,2366,2368],{"class":2354,"line":2367},3,[43,2369,2358],{},[43,2371,2373],{"class":2354,"line":2372},4,[43,2374,2375],{},"# x_train -> variável de ENTRADA (feature): tamanho da casa, em milhares de pés²\n",[43,2377,2379],{"class":2354,"line":2378},5,[43,2380,2381],{},"# y_train -> variável ALVO (target):        preço da casa, em milhares de dólares\n",[43,2383,2385],{"class":2354,"line":2384},6,[43,2386,2387],{},"# A ordem importa: x_train[0] e y_train[0] descrevem a MESMA casa.\n",[43,2389,2391],{"class":2354,"line":2390},7,[43,2392,2394],{"emptyLinePlaceholder":2393},true,"\n",[43,2396,2398],{"class":2354,"line":2397},8,[43,2399,2400],{},"x_train = np.array([1.0, 2.0])       # Cria um array NumPy 1-D com os dois tamanhos.\n",[43,2402,2404],{"class":2354,"line":2403},9,[43,2405,2406],{},"y_train = np.array([300.0, 500.0])   # Cria um array NumPy 1-D com os dois preços correspondentes.\n",[43,2408,2410],{"class":2354,"line":2409},10,[43,2411,2394],{"emptyLinePlaceholder":2393},[43,2413,2415],{"class":2354,"line":2414},11,[43,2416,2417],{},"print(f\"x_train = {x_train}\")\n",[43,2419,2421],{"class":2354,"line":2420},12,[43,2422,2423],{},"print(f\"y_train = {y_train}\")\n",[11,2425,2426,2431],{},[14,2427,2428],{},[18,2429,2430],{},"Saída:",[2344,2432,2437],{"className":2433,"code":2435,"language":2436},[2434],"language-text","x_train = [1. 2.]\ny_train = [300. 500.]\n","text",[33,2438,2435],{"__ignoreMap":2349},[14,2440,2441,2442,2445,2446,2449,2450,2453],{},"Repara que usei ",[33,2443,2444],{},"np.array",", não uma lista Python normal (",[33,2447,2448],{},"[1.0, 2.0]"," puro). Não é frescura de biblioteca chique: array NumPy guarda os números \"grudados\" na memória e faz conta em cima de todo mundo de uma vez (isso chama ",[18,2451,2452],{},"vetorização","), em vez de percorrer item por item como uma lista faria. Com 2 números não faz diferença nenhuma, mas com 2 milhões é a diferença entre rodar em segundos ou travar sua máquina. Todo o curso, e praticamente todo código sério de ML, parte do NumPy por causa disso.",[11,2455,2456],{},[14,2457,2458,2461,2462,2464,2465,2468,2469,2472],{},[18,2459,2460],{},"Sobre f-strings:"," o ",[33,2463,67],{}," antes das aspas é Python avaliando o que tá dentro de ",[33,2466,2467],{},"{ }"," e enfiando no texto. ",[33,2470,2471],{},"{valor:.2f}"," formata com 2 casas decimais. Vai aparecer o tempo todo daqui pra frente.",[2339,2474,2476,2477,90],{"id":2475},"quantos-exemplos-eu-tenho-mmm","Quantos exemplos eu tenho? (",[43,2478,2480,2493],{"className":2479},[46],[43,2481,2483],{"className":2482},[50],[52,2484,2485],{"xmlns":54},[56,2486,2487,2491],{},[59,2488,2489],{},[65,2490,285],{},[108,2492,285],{"encoding":110},[43,2494,2496],{"className":2495,"ariaHidden":76},[115],[43,2497,2499,2502],{"className":2498},[119],[43,2500],{"className":2501,"style":297},[123],[43,2503,285],{"className":2504},[128,132],[2344,2506,2508],{"className":2346,"code":2507,"language":2348,"meta":2349,"style":2349},"# Via .shape -- devolve uma TUPLA com o tamanho de cada dimensão.\nprint(f\"x_train.shape: {x_train.shape}\")   # (2,) para um vetor 1-D com 2 elementos.\nm = x_train.shape[0]\nprint(f\"Número de exemplos de treino é: {m}\")\n\n# Via len() -- funciona em arrays NumPy como funciona em listas.\nm = len(x_train)\nprint(f\"Número de exemplos de treino é: {m}\")\n",[33,2509,2510,2515,2520,2525,2530,2534,2539,2544],{"__ignoreMap":2349},[43,2511,2512],{"class":2354,"line":2355},[43,2513,2514],{},"# Via .shape -- devolve uma TUPLA com o tamanho de cada dimensão.\n",[43,2516,2517],{"class":2354,"line":2361},[43,2518,2519],{},"print(f\"x_train.shape: {x_train.shape}\")   # (2,) para um vetor 1-D com 2 elementos.\n",[43,2521,2522],{"class":2354,"line":2367},[43,2523,2524],{},"m = x_train.shape[0]\n",[43,2526,2527],{"class":2354,"line":2372},[43,2528,2529],{},"print(f\"Número de exemplos de treino é: {m}\")\n",[43,2531,2532],{"class":2354,"line":2378},[43,2533,2394],{"emptyLinePlaceholder":2393},[43,2535,2536],{"class":2354,"line":2384},[43,2537,2538],{},"# Via len() -- funciona em arrays NumPy como funciona em listas.\n",[43,2540,2541],{"class":2354,"line":2390},[43,2542,2543],{},"m = len(x_train)\n",[43,2545,2546],{"class":2354,"line":2397},[43,2547,2529],{},[14,2549,2550,2551,2554,2555,2607,2608,2610,2611,2614,2615,2618],{},"As duas dão o mesmo resultado aqui, mas eu peguei o hábito de usar ",[33,2552,2553],{},".shape"," cedo, e vale a pena você pegar também: quando seus dados tiverem várias colunas (aquele ",[43,2556,2558,2577],{"className":2557},[46],[43,2559,2561],{"className":2560},[50],[52,2562,2563],{"xmlns":54},[56,2564,2565,2574],{},[59,2566,2567,2569,2572],{},[65,2568,285],{},[74,2570,2571],{},"×",[65,2573,1450],{},[108,2575,2576],{"encoding":110},"m \\times n",[43,2578,2580,2598],{"className":2579,"ariaHidden":76},[115],[43,2581,2583,2586,2589,2592,2595],{"className":2582},[119],[43,2584],{"className":2585,"style":224},[123],[43,2587,285],{"className":2588},[128,132],[43,2590],{"className":2591,"style":238},[209],[43,2593,2571],{"className":2594},[242],[43,2596],{"className":2597,"style":238},[209],[43,2599,2601,2604],{"className":2600},[119],[43,2602],{"className":2603,"style":297},[123],[43,2605,1450],{"className":2606},[128,132]," que falei ali em cima), ",[33,2609,2553],{}," te conta linhas ",[2334,2612,2613],{},"e"," colunas de cara, enquanto ",[33,2616,2617],{},"len()"," só te dá o número de linhas e te deixa no escuro sobre o resto.",[2339,2620,2622],{"id":2621},"pescando-um-exemplo-específico","Pescando um exemplo específico",[14,2624,2625,2626,2629],{},"Python conta a partir do ",[18,2627,2628],{},"zero",", sempre:",[484,2631,2632,2813],{},[487,2633,2634],{},[490,2635,2636,2667,2811],{},[493,2637,2638,2639],{"align":1616},"Índice ",[43,2640,2642,2655],{"className":2641},[46],[43,2643,2645],{"className":2644},[50],[52,2646,2647],{"xmlns":54},[56,2648,2649,2653],{},[59,2650,2651],{},[65,2652,699],{},[108,2654,699],{"encoding":110},[43,2656,2658],{"className":2657,"ariaHidden":76},[115],[43,2659,2661,2664],{"className":2660},[119],[43,2662],{"className":2663,"style":858},[123],[43,2665,699],{"className":2666},[128,132],[493,2668,2669],{"align":1616},[43,2670,2672,2714],{"className":2671},[46],[43,2673,2675],{"className":2674},[50],[52,2676,2677],{"xmlns":54},[56,2678,2679,2711],{},[59,2680,2681,2683,2695,2697,2709],{},[74,2682,84],{"stretchy":83},[689,2684,2685,2687],{},[65,2686,87],{},[59,2688,2689,2691,2693],{},[74,2690,84],{"stretchy":83},[65,2692,699],{},[74,2694,90],{"stretchy":83},[74,2696,77],{"separator":76},[689,2698,2699,2701],{},[65,2700,646],{},[59,2702,2703,2705,2707],{},[74,2704,84],{"stretchy":83},[65,2706,699],{},[74,2708,90],{"stretchy":83},[74,2710,90],{"stretchy":83},[108,2712,2713],{"encoding":110},"(x^{(i)}, y^{(i)})",[43,2715,2717],{"className":2716,"ariaHidden":76},[115],[43,2718,2720,2723,2726,2764,2767,2770,2808],{"className":2719},[119],[43,2721],{"className":2722,"style":1945},[123],[43,2724,84],{"className":2725},[198],[43,2727,2729,2732],{"className":2728},[128],[43,2730,87],{"className":2731},[128,132],[43,2733,2735],{"className":2734},[137],[43,2736,2738],{"className":2737},[141],[43,2739,2741],{"className":2740},[146],[43,2742,2744],{"className":2743,"style":714},[150],[43,2745,2746,2749],{"style":735},[43,2747],{"className":2748,"style":159},[158],[43,2750,2752],{"className":2751},[163,164,165,166],[43,2753,2755,2758,2761],{"className":2754},[128,166],[43,2756,84],{"className":2757},[198,166],[43,2759,699],{"className":2760},[128,132,166],[43,2762,90],{"className":2763},[205,166],[43,2765,77],{"className":2766},[177],[43,2768],{"className":2769,"style":231},[209],[43,2771,2773,2776],{"className":2772},[128],[43,2774,646],{"className":2775,"style":797},[128,132],[43,2777,2779],{"className":2778},[137],[43,2780,2782],{"className":2781},[141],[43,2783,2785],{"className":2784},[146],[43,2786,2788],{"className":2787,"style":714},[150],[43,2789,2790,2793],{"style":735},[43,2791],{"className":2792,"style":159},[158],[43,2794,2796],{"className":2795},[163,164,165,166],[43,2797,2799,2802,2805],{"className":2798},[128,166],[43,2800,84],{"className":2801},[198,166],[43,2803,699],{"className":2804},[128,132,166],[43,2806,90],{"className":2807},[205,166],[43,2809,90],{"className":2810},[205],[493,2812,502],{"align":495},[504,2814,2815,2886],{},[490,2816,2817,2819,2878],{},[509,2818,1803],{"align":1616},[509,2820,2821],{"align":1616},[43,2822,2824,2848],{"className":2823},[46],[43,2825,2827],{"className":2826},[50],[52,2828,2829],{"xmlns":54},[56,2830,2831,2845],{},[59,2832,2833,2835,2837,2839,2841,2843],{},[74,2834,84],{"stretchy":83},[1284,2836,1806],{},[74,2838,77],{"separator":76},[97,2840,1927],{},[1284,2842,1930],{},[74,2844,90],{"stretchy":83},[108,2846,2847],{"encoding":110},"(1.0,\\ 300.0)",[43,2849,2851],{"className":2850,"ariaHidden":76},[115],[43,2852,2854,2857,2860,2863,2866,2869,2872,2875],{"className":2853},[119],[43,2855],{"className":2856,"style":2049},[123],[43,2858,84],{"className":2859},[198],[43,2861,1806],{"className":2862},[128],[43,2864,77],{"className":2865},[177],[43,2867,1927],{"className":2868},[209],[43,2870],{"className":2871,"style":231},[209],[43,2873,1930],{"className":2874},[128],[43,2876,90],{"className":2877},[205],[509,2879,2880,467,2883],{"align":495},[33,2881,2882],{},"x_train[0]",[33,2884,2885],{},"y_train[0]",[490,2887,2888,2890,2949],{},[509,2889,1546],{"align":1616},[509,2891,2892],{"align":1616},[43,2893,2895,2919],{"className":2894},[46],[43,2896,2898],{"className":2897},[50],[52,2899,2900],{"xmlns":54},[56,2901,2902,2916],{},[59,2903,2904,2906,2908,2910,2912,2914],{},[74,2905,84],{"stretchy":83},[1284,2907,1816],{},[74,2909,77],{"separator":76},[97,2911,1927],{},[1284,2913,2125],{},[74,2915,90],{"stretchy":83},[108,2917,2918],{"encoding":110},"(2.0,\\ 500.0)",[43,2920,2922],{"className":2921,"ariaHidden":76},[115],[43,2923,2925,2928,2931,2934,2937,2940,2943,2946],{"className":2924},[119],[43,2926],{"className":2927,"style":2049},[123],[43,2929,84],{"className":2930},[198],[43,2932,1816],{"className":2933},[128],[43,2935,77],{"className":2936},[177],[43,2938,1927],{"className":2939},[209],[43,2941],{"className":2942,"style":231},[209],[43,2944,2125],{"className":2945},[128],[43,2947,90],{"className":2948},[205],[509,2950,2951,467,2954],{"align":495},[33,2952,2953],{},"x_train[1]",[33,2955,2956],{},"y_train[1]",[2344,2958,2960],{"className":2346,"code":2959,"language":2348,"meta":2349,"style":2349},"i = 0                    # Índice do exemplo que queremos inspecionar.\nx_i = x_train[i]\ny_i = y_train[i]\n\nprint(f\"(x^({i}), y^({i})) = ({x_i}, {y_i})\")\n",[33,2961,2962,2967,2972,2977,2981],{"__ignoreMap":2349},[43,2963,2964],{"class":2354,"line":2355},[43,2965,2966],{},"i = 0                    # Índice do exemplo que queremos inspecionar.\n",[43,2968,2969],{"class":2354,"line":2361},[43,2970,2971],{},"x_i = x_train[i]\n",[43,2973,2974],{"class":2354,"line":2367},[43,2975,2976],{},"y_i = y_train[i]\n",[43,2978,2979],{"class":2354,"line":2372},[43,2980,2394],{"emptyLinePlaceholder":2393},[43,2982,2983],{"class":2354,"line":2378},[43,2984,2985],{},"print(f\"(x^({i}), y^({i})) = ({x_i}, {y_i})\")\n",[11,2987,2988],{},[14,2989,2990,1254,2992],{},[18,2991,2430],{},[33,2993,2994],{},"(x^(0), y^(0)) = (1.0, 300.0)",[14,2996,2997,2998,3072,3073,3075],{},"Detalhe chato que pega gente boa: nas aulas às vezes o Andrew Ng conta a partir de 1 (",[43,2999,3001,3025],{"className":3000},[46],[43,3002,3004],{"className":3003},[50],[52,3005,3006],{"xmlns":54},[56,3007,3008,3022],{},[59,3009,3010],{},[689,3011,3012,3014],{},[65,3013,87],{},[59,3015,3016,3018,3020],{},[74,3017,84],{"stretchy":83},[1284,3019,1546],{},[74,3021,90],{"stretchy":83},[108,3023,3024],{"encoding":110},"x^{(1)}",[43,3026,3028],{"className":3027,"ariaHidden":76},[115],[43,3029,3031,3034],{"className":3030},[119],[43,3032],{"className":3033,"style":714},[123],[43,3035,3037,3040],{"className":3036},[128],[43,3038,87],{"className":3039},[128,132],[43,3041,3043],{"className":3042},[137],[43,3044,3046],{"className":3045},[141],[43,3047,3049],{"className":3048},[146],[43,3050,3052],{"className":3051,"style":714},[150],[43,3053,3054,3057],{"style":735},[43,3055],{"className":3056,"style":159},[158],[43,3058,3060],{"className":3059},[163,164,165,166],[43,3061,3063,3066,3069],{"className":3062},[128,166],[43,3064,84],{"className":3065},[198,166],[43,3067,1546],{"className":3068},[128,166],[43,3070,90],{"className":3071},[205,166]," sendo o primeiro exemplo). No código, o primeiro é sempre ",[33,3074,2882],{},". É a mesma casa, só muda a régua de contagem. Não é bug seu se der um \"off-by-one\" na cabeça, é padrão da área mesmo.",[257,3077,3079],{"id":3078},"olha-pros-dados-antes-de-sair-modelando","Olha pros dados antes de sair modelando",[14,3081,3082],{},"Isso não é conselho de \"boa prática\" genérico, é regra de sobrevivência. Se você sair direto ajustando reta sem olhar o formato dos dados, você não vai perceber quando a relação não é nem de longe linear (e aí regressão linear seria a ferramenta errada pro trabalho). Um gráfico de dispersão resolve isso em 2 segundos de olhada. Passa o mouse nos pontos:",[3084,3085],"model-prediction-chart",{":x-train":3086,":y-train":3087,"dataLabel":3088,"x-label":3089,"y-label":3090},"[1, 2]","[300, 500]","Dados de treino","Tamanho (1000 pés²)","Preço (1000 dólares)",[14,3092,3093],{},"Com só 2 pontos, \"linear ou não\" é meio óbvio, mas o hábito de olhar antes é o que importa aqui, porque com 200 ou 2000 pontos ele vai te salvar de horas perdidas tentando ajustar o modelo errado.",[257,3095,3097],{"id":3096},"a-função-do-modelo-o-que-w-e-b-realmente-significam","A função do modelo: o que w e b realmente significam",[14,3099,3100],{},[43,3101,3103,3165],{"className":3102},[46],[43,3104,3106],{"className":3105},[50],[52,3107,3108],{"xmlns":54},[56,3109,3110,3162],{},[59,3111,3112,3124,3126,3138,3140,3142,3144,3146,3158,3160],{},[62,3113,3114,3116],{},[65,3115,67],{},[59,3117,3118,3120,3122],{},[65,3119,72],{},[74,3121,77],{"separator":76},[65,3123,80],{},[74,3125,84],{"stretchy":83},[689,3127,3128,3130],{},[65,3129,87],{},[59,3131,3132,3134,3136],{},[74,3133,84],{"stretchy":83},[65,3135,699],{},[74,3137,90],{"stretchy":83},[74,3139,90],{"stretchy":83},[74,3141,93],{},[65,3143,72],{},[97,3145,99],{},[689,3147,3148,3150],{},[65,3149,87],{},[59,3151,3152,3154,3156],{},[74,3153,84],{"stretchy":83},[65,3155,699],{},[74,3157,90],{"stretchy":83},[74,3159,104],{},[65,3161,80],{},[108,3163,3164],{"encoding":110},"f_{w,b}(x^{(i)}) = w\\,x^{(i)} + b",[43,3166,3168,3276,3336],{"className":3167,"ariaHidden":76},[115],[43,3169,3171,3174,3223,3226,3264,3267,3270,3273],{"className":3170},[119],[43,3172],{"className":3173,"style":1043},[123],[43,3175,3177,3180],{"className":3176},[128],[43,3178,67],{"className":3179,"style":133},[128,132],[43,3181,3183],{"className":3182},[137],[43,3184,3186,3215],{"className":3185},[141,142],[43,3187,3189,3212],{"className":3188},[146],[43,3190,3192],{"className":3191,"style":151},[150],[43,3193,3194,3197],{"style":154},[43,3195],{"className":3196,"style":159},[158],[43,3198,3200],{"className":3199},[163,164,165,166],[43,3201,3203,3206,3209],{"className":3202},[128,166],[43,3204,72],{"className":3205,"style":173},[128,132,166],[43,3207,77],{"className":3208},[177,166],[43,3210,80],{"className":3211},[128,132,166],[43,3213,185],{"className":3214},[184],[43,3216,3218],{"className":3217},[146],[43,3219,3221],{"className":3220,"style":192},[150],[43,3222],{},[43,3224,84],{"className":3225},[198],[43,3227,3229,3232],{"className":3228},[128],[43,3230,87],{"className":3231},[128,132],[43,3233,3235],{"className":3234},[137],[43,3236,3238],{"className":3237},[141],[43,3239,3241],{"className":3240},[146],[43,3242,3244],{"className":3243,"style":714},[150],[43,3245,3246,3249],{"style":735},[43,3247],{"className":3248,"style":159},[158],[43,3250,3252],{"className":3251},[163,164,165,166],[43,3253,3255,3258,3261],{"className":3254},[128,166],[43,3256,84],{"className":3257},[198,166],[43,3259,699],{"className":3260},[128,132,166],[43,3262,90],{"className":3263},[205,166],[43,3265,90],{"className":3266},[205],[43,3268],{"className":3269,"style":210},[209],[43,3271,93],{"className":3272},[214],[43,3274],{"className":3275,"style":210},[209],[43,3277,3279,3283,3286,3289,3327,3330,3333],{"className":3278},[119],[43,3280],{"className":3281,"style":3282},[123],"height:0.9713em;vertical-align:-0.0833em;",[43,3284,72],{"className":3285,"style":173},[128,132],[43,3287],{"className":3288,"style":231},[209],[43,3290,3292,3295],{"className":3291},[128],[43,3293,87],{"className":3294},[128,132],[43,3296,3298],{"className":3297},[137],[43,3299,3301],{"className":3300},[141],[43,3302,3304],{"className":3303},[146],[43,3305,3307],{"className":3306,"style":714},[150],[43,3308,3309,3312],{"style":735},[43,3310],{"className":3311,"style":159},[158],[43,3313,3315],{"className":3314},[163,164,165,166],[43,3316,3318,3321,3324],{"className":3317},[128,166],[43,3319,84],{"className":3320},[198,166],[43,3322,699],{"className":3323},[128,132,166],[43,3325,90],{"className":3326},[205,166],[43,3328],{"className":3329,"style":238},[209],[43,3331,104],{"className":3332},[242],[43,3334],{"className":3335,"style":238},[209],[43,3337,3339,3342],{"className":3338},[119],[43,3340],{"className":3341,"style":252},[123],[43,3343,80],{"className":3344},[128,132],[14,3346,3347,3348,3351,3352,3355,3356,1581],{},"Beleza, é a equação de uma reta. Mas \"inclinação\" e \"intercepto\" são termos meio secos, deixa eu te dar uma imagem melhor: pensa num aplicativo de corrida tipo Uber. Toda corrida tem uma ",[18,3349,3350],{},"taxa fixa de embarque"," (você paga isso só por entrar no carro, não importa a distância) e um ",[18,3353,3354],{},"valor por quilômetro rodado",". O preço final é ",[33,3357,3358],{},"taxa_fixa + valor_por_km * distância",[14,3360,3361,3362,3510],{},"Bate exatamente com ",[43,3363,3365,3404],{"className":3364},[46],[43,3366,3368],{"className":3367},[50],[52,3369,3370],{"xmlns":54},[56,3371,3372,3402],{},[59,3373,3374,3386,3388,3390,3392,3394,3396,3398,3400],{},[62,3375,3376,3378],{},[65,3377,67],{},[59,3379,3380,3382,3384],{},[65,3381,72],{},[74,3383,77],{"separator":76},[65,3385,80],{},[74,3387,84],{"stretchy":83},[65,3389,87],{},[74,3391,90],{"stretchy":83},[74,3393,93],{},[65,3395,72],{},[65,3397,87],{},[74,3399,104],{},[65,3401,80],{},[108,3403,350],{"encoding":110},[43,3405,3407,3480,3501],{"className":3406,"ariaHidden":76},[115],[43,3408,3410,3413,3462,3465,3468,3471,3474,3477],{"className":3409},[119],[43,3411],{"className":3412,"style":124},[123],[43,3414,3416,3419],{"className":3415},[128],[43,3417,67],{"className":3418,"style":133},[128,132],[43,3420,3422],{"className":3421},[137],[43,3423,3425,3454],{"className":3424},[141,142],[43,3426,3428,3451],{"className":3427},[146],[43,3429,3431],{"className":3430,"style":151},[150],[43,3432,3433,3436],{"style":154},[43,3434],{"className":3435,"style":159},[158],[43,3437,3439],{"className":3438},[163,164,165,166],[43,3440,3442,3445,3448],{"className":3441},[128,166],[43,3443,72],{"className":3444,"style":173},[128,132,166],[43,3446,77],{"className":3447},[177,166],[43,3449,80],{"className":3450},[128,132,166],[43,3452,185],{"className":3453},[184],[43,3455,3457],{"className":3456},[146],[43,3458,3460],{"className":3459,"style":192},[150],[43,3461],{},[43,3463,84],{"className":3464},[198],[43,3466,87],{"className":3467},[128,132],[43,3469,90],{"className":3470},[205],[43,3472],{"className":3473,"style":210},[209],[43,3475,93],{"className":3476},[214],[43,3478],{"className":3479,"style":210},[209],[43,3481,3483,3486,3489,3492,3495,3498],{"className":3482},[119],[43,3484],{"className":3485,"style":224},[123],[43,3487,72],{"className":3488,"style":173},[128,132],[43,3490,87],{"className":3491},[128,132],[43,3493],{"className":3494,"style":238},[209],[43,3496,104],{"className":3497},[242],[43,3499],{"className":3500,"style":238},[209],[43,3502,3504,3507],{"className":3503},[119],[43,3505],{"className":3506,"style":252},[123],[43,3508,80],{"className":3509},[128,132],":",[484,3512,3513,3529],{},[487,3514,3515],{},[490,3516,3517,3520,3523,3526],{},[493,3518,3519],{"align":1616},"Parâmetro",[493,3521,3522],{"align":495},"No Uber",[493,3524,3525],{"align":495},"Aqui",[493,3527,3528],{"align":495},"Significado geométrico",[504,3530,3531,3575],{},[490,3532,3533,3563,3566,3569],{},[509,3534,3535],{"align":1616},[43,3536,3538,3551],{"className":3537},[46],[43,3539,3541],{"className":3540},[50],[52,3542,3543],{"xmlns":54},[56,3544,3545,3549],{},[59,3546,3547],{},[65,3548,72],{},[108,3550,72],{"encoding":110},[43,3552,3554],{"className":3553,"ariaHidden":76},[115],[43,3555,3557,3560],{"className":3556},[119],[43,3558],{"className":3559,"style":297},[123],[43,3561,72],{"className":3562,"style":173},[128,132],[509,3564,3565],{"align":495},"valor por km rodado",[509,3567,3568],{"align":495},"quanto o preço sobe por 1000 pés² a mais",[509,3570,3571,3574],{"align":495},[18,3572,3573],{},"inclinação"," da reta",[490,3576,3577,3607,3609,3612],{},[509,3578,3579],{"align":1616},[43,3580,3582,3595],{"className":3581},[46],[43,3583,3585],{"className":3584},[50],[52,3586,3587],{"xmlns":54},[56,3588,3589,3593],{},[59,3590,3591],{},[65,3592,80],{},[108,3594,80],{"encoding":110},[43,3596,3598],{"className":3597,"ariaHidden":76},[115],[43,3599,3601,3604],{"className":3600},[119],[43,3602],{"className":3603,"style":252},[123],[43,3605,80],{"className":3606},[128,132],[509,3608,3350],{"align":495},[509,3610,3611],{"align":495},"preço-base, quando o tamanho é zero",[509,3613,3614,3617],{"align":495},[18,3615,3616],{},"intercepto"," (onde a reta cruza o eixo vertical)",[14,3619,3620,3621,3649,3650,3678,3679,471,3707,3735],{},"Se ",[43,3622,3624,3637],{"className":3623},[46],[43,3625,3627],{"className":3626},[50],[52,3628,3629],{"xmlns":54},[56,3630,3631,3635],{},[59,3632,3633],{},[65,3634,72],{},[108,3636,72],{"encoding":110},[43,3638,3640],{"className":3639,"ariaHidden":76},[115],[43,3641,3643,3646],{"className":3642},[119],[43,3644],{"className":3645,"style":297},[123],[43,3647,72],{"className":3648,"style":173},[128,132]," é grande, cada km (ou cada 1000 pés²) pesa mais no preço final: a reta sobe rápido. Se ",[43,3651,3653,3666],{"className":3652},[46],[43,3654,3656],{"className":3655},[50],[52,3657,3658],{"xmlns":54},[56,3659,3660,3664],{},[59,3661,3662],{},[65,3663,80],{},[108,3665,80],{"encoding":110},[43,3667,3669],{"className":3668,"ariaHidden":76},[115],[43,3670,3672,3675],{"className":3671},[119],[43,3673],{"className":3674,"style":252},[123],[43,3676,80],{"className":3677},[128,132]," é grande, você já começa \"pagando caro\" antes de andar um metro, e a reta nasce mais alto no eixo vertical. Combinações diferentes de ",[43,3680,3682,3695],{"className":3681},[46],[43,3683,3685],{"className":3684},[50],[52,3686,3687],{"xmlns":54},[56,3688,3689,3693],{},[59,3690,3691],{},[65,3692,72],{},[108,3694,72],{"encoding":110},[43,3696,3698],{"className":3697,"ariaHidden":76},[115],[43,3699,3701,3704],{"className":3700},[119],[43,3702],{"className":3703,"style":297},[123],[43,3705,72],{"className":3706,"style":173},[128,132],[43,3708,3710,3723],{"className":3709},[46],[43,3711,3713],{"className":3712},[50],[52,3714,3715],{"xmlns":54},[56,3716,3717,3721],{},[59,3718,3719],{},[65,3720,80],{},[108,3722,80],{"encoding":110},[43,3724,3726],{"className":3725,"ariaHidden":76},[115],[43,3727,3729,3732],{"className":3728},[119],[43,3730],{"className":3731,"style":252},[123],[43,3733,80],{"className":3734},[128,132]," desenham retas completamente diferentes.",[14,3737,3738,3794,3795,3798,3799,471,3803,3807,3808,3811],{},[18,3739,3740,3741,3793],{},"Foi aí que eu entendi: treinar o modelo é justamente achar o par ",[43,3742,3744,3766],{"className":3743},[46],[43,3745,3747],{"className":3746},[50],[52,3748,3749],{"xmlns":54},[56,3750,3751,3763],{},[59,3752,3753,3755,3757,3759,3761],{},[74,3754,84],{"stretchy":83},[65,3756,72],{},[74,3758,77],{"separator":76},[65,3760,80],{},[74,3762,90],{"stretchy":83},[108,3764,3765],{"encoding":110},"(w, b)",[43,3767,3769],{"className":3768,"ariaHidden":76},[115],[43,3770,3772,3775,3778,3781,3784,3787,3790],{"className":3771},[119],[43,3773],{"className":3774,"style":2049},[123],[43,3776,84],{"className":3777},[198],[43,3779,72],{"className":3780,"style":173},[128,132],[43,3782,77],{"className":3783},[177],[43,3785],{"className":3786,"style":231},[209],[43,3788,80],{"className":3789},[128,132],[43,3791,90],{"className":3792},[205]," que melhor descreve os dados que você tem."," Só que a gente ainda não viu ",[2334,3796,3797],{},"como"," automatizar essa busca (isso é assunto dos próximos dois posts: ",[525,3800,3802],{"href":3801},"\u002Fplaylists\u002Fmachine-learning-specialization\u002Flab03-cost-function","função de custo",[525,3804,3806],{"href":3805},"\u002Fplaylists\u002Fmachine-learning-specialization\u002Flab04-gradient-descent","gradiente descendente","). Por enquanto, vamos fazer isso ",[18,3809,3810],{},"na mão mesmo",", chutando valores, pra você sentir na pele o problema que esses próximos posts resolvem.",[2339,3813,3815],{"id":3814},"transformando-a-fórmula-em-função","Transformando a fórmula em função",[14,3817,3818,3819,471,3822,3825],{},"Com 2 pontos, eu conseguia calcular ",[33,3820,3821],{},"w * x[0] + b",[33,3823,3824],{},"w * x[1] + b"," na mão. Com mil pontos isso vira trabalho braçal inútil, e é exatamente esse tipo de repetição chata que a gente empacota numa função:",[2344,3827,3829],{"className":2346,"code":3828,"language":2348,"meta":2349,"style":2349},"def compute_model_output(x, w, b):\n    \"\"\"\n    Calcula a previsão de um modelo linear f_wb(x) = w*x + b.\n\n    Args:\n      x (ndarray (m,)) : dados de entrada, m exemplos (a feature)\n      w, b (scalar)    : parâmetros do modelo (peso e viés)\n\n    Returns:\n      f_wb (ndarray (m,)) : previsão do modelo para cada exemplo de x\n    \"\"\"\n    m = x.shape[0]              # 1) Quantos exemplos existem no array de entrada.\n    f_wb = np.zeros(m)          # 2) Recipiente de saída: array de m zeros.\n\n    for i in range(m):          # 3) Percorre i = 0, 1, ..., m-1.\n        f_wb[i] = w * x[i] + b  #    Aplica a equação da reta ao exemplo i.\n\n    return f_wb                 # Devolve o array completo de previsões.\n",[33,3830,3831,3836,3841,3846,3850,3855,3860,3865,3869,3874,3879,3883,3888,3894,3899,3905,3911,3916],{"__ignoreMap":2349},[43,3832,3833],{"class":2354,"line":2355},[43,3834,3835],{},"def compute_model_output(x, w, b):\n",[43,3837,3838],{"class":2354,"line":2361},[43,3839,3840],{},"    \"\"\"\n",[43,3842,3843],{"class":2354,"line":2367},[43,3844,3845],{},"    Calcula a previsão de um modelo linear f_wb(x) = w*x + b.\n",[43,3847,3848],{"class":2354,"line":2372},[43,3849,2394],{"emptyLinePlaceholder":2393},[43,3851,3852],{"class":2354,"line":2378},[43,3853,3854],{},"    Args:\n",[43,3856,3857],{"class":2354,"line":2384},[43,3858,3859],{},"      x (ndarray (m,)) : dados de entrada, m exemplos (a feature)\n",[43,3861,3862],{"class":2354,"line":2390},[43,3863,3864],{},"      w, b (scalar)    : parâmetros do modelo (peso e viés)\n",[43,3866,3867],{"class":2354,"line":2397},[43,3868,2394],{"emptyLinePlaceholder":2393},[43,3870,3871],{"class":2354,"line":2403},[43,3872,3873],{},"    Returns:\n",[43,3875,3876],{"class":2354,"line":2409},[43,3877,3878],{},"      f_wb (ndarray (m,)) : previsão do modelo para cada exemplo de x\n",[43,3880,3881],{"class":2354,"line":2414},[43,3882,3840],{},[43,3884,3885],{"class":2354,"line":2420},[43,3886,3887],{},"    m = x.shape[0]              # 1) Quantos exemplos existem no array de entrada.\n",[43,3889,3891],{"class":2354,"line":3890},13,[43,3892,3893],{},"    f_wb = np.zeros(m)          # 2) Recipiente de saída: array de m zeros.\n",[43,3895,3897],{"class":2354,"line":3896},14,[43,3898,2394],{"emptyLinePlaceholder":2393},[43,3900,3902],{"class":2354,"line":3901},15,[43,3903,3904],{},"    for i in range(m):          # 3) Percorre i = 0, 1, ..., m-1.\n",[43,3906,3908],{"class":2354,"line":3907},16,[43,3909,3910],{},"        f_wb[i] = w * x[i] + b  #    Aplica a equação da reta ao exemplo i.\n",[43,3912,3914],{"class":2354,"line":3913},17,[43,3915,2394],{"emptyLinePlaceholder":2393},[43,3917,3919],{"class":2354,"line":3918},18,[43,3920,3921],{},"    return f_wb                 # Devolve o array completo de previsões.\n",[14,3923,3924,3925,467,3927,467,3929,3931],{},"Guardei isso numa função com contrato claro (entra ",[33,3926,87],{},[33,3928,72],{},[33,3930,80],{},", sai um array de previsões), e isso significa que ela funciona pra 2 exemplos, 2 mil ou 2 milhões, sem você reescrever nada. É um detalhe chato de engenharia, mas é esse tipo de detalhe que separa \"script que roda uma vez\" de \"código que aguenta um sistema de verdade\".",[257,3933,3935],{"id":3934},"agora-é-a-sua-vez-acha-o-ajuste-perfeito","Agora é a sua vez: acha o ajuste perfeito",[14,3937,3938,3939,3942,3943,471,3971,3999,4000,4003],{},"Aqui embaixo tem um gráfico ",[2334,3940,3941],{},"de verdade"," interativo: arraste os sliders de ",[43,3944,3946,3959],{"className":3945},[46],[43,3947,3949],{"className":3948},[50],[52,3950,3951],{"xmlns":54},[56,3952,3953,3957],{},[59,3954,3955],{},[65,3956,72],{},[108,3958,72],{"encoding":110},[43,3960,3962],{"className":3961,"ariaHidden":76},[115],[43,3963,3965,3968],{"className":3964},[119],[43,3966],{"className":3967,"style":297},[123],[43,3969,72],{"className":3970,"style":173},[128,132],[43,3972,3974,3987],{"className":3973},[46],[43,3975,3977],{"className":3976},[50],[52,3978,3979],{"xmlns":54},[56,3980,3981,3985],{},[59,3982,3983],{},[65,3984,80],{},[108,3986,80],{"encoding":110},[43,3988,3990],{"className":3989,"ariaHidden":76},[115],[43,3991,3993,3996],{"className":3992},[119],[43,3994],{"className":3995,"style":252},[123],[43,3997,80],{"className":3998},[128,132]," e observa três coisas ao mesmo tempo: a linha azul (a previsão do seu modelo), as linhas pontilhadas cinzas (a distância entre cada previsão e o valor real, isso é o ",[18,4001,4002],{},"erro"," de cada exemplo) e o número de \"Erro total\" embaixo do gráfico.",[14,4005,4006,4007,467,4059,4110,4111,4114],{},"Começa em ",[43,4008,4010,4029],{"className":4009},[46],[43,4011,4013],{"className":4012},[50],[52,4014,4015],{"xmlns":54},[56,4016,4017,4026],{},[59,4018,4019,4021,4023],{},[65,4020,72],{},[74,4022,93],{},[1284,4024,4025],{},"100",[108,4027,4028],{"encoding":110},"w=100",[43,4030,4032,4050],{"className":4031,"ariaHidden":76},[115],[43,4033,4035,4038,4041,4044,4047],{"className":4034},[119],[43,4036],{"className":4037,"style":297},[123],[43,4039,72],{"className":4040,"style":173},[128,132],[43,4042],{"className":4043,"style":210},[209],[43,4045,93],{"className":4046},[214],[43,4048],{"className":4049,"style":210},[209],[43,4051,4053,4056],{"className":4052},[119],[43,4054],{"className":4055,"style":1577},[123],[43,4057,4025],{"className":4058},[128],[43,4060,4062,4080],{"className":4061},[46],[43,4063,4065],{"className":4064},[50],[52,4066,4067],{"xmlns":54},[56,4068,4069,4077],{},[59,4070,4071,4073,4075],{},[65,4072,80],{},[74,4074,93],{},[1284,4076,4025],{},[108,4078,4079],{"encoding":110},"b=100",[43,4081,4083,4101],{"className":4082,"ariaHidden":76},[115],[43,4084,4086,4089,4092,4095,4098],{"className":4085},[119],[43,4087],{"className":4088,"style":252},[123],[43,4090,80],{"className":4091},[128,132],[43,4093],{"className":4094,"style":210},[209],[43,4096,93],{"className":4097},[214],[43,4099],{"className":4100,"style":210},[209],[43,4102,4104,4107],{"className":4103},[119],[43,4105],{"className":4106,"style":1577},[123],[43,4108,4025],{"className":4109},[128]," (o primeiro chute do notebook original), repara como a linha fica longe dos losangos vermelhos, e o erro total é grande. ",[18,4112,4113],{},"Seu desafio:"," mexe nos sliders até o erro total zerar.",[14,4116,4117],{},"Duas dicas, se quiser pensar antes de sair arrastando no chute:",[262,4119,4120,4154],{},[265,4121,4122,4153],{},[18,4123,4124,4125],{},"A inclinação ",[43,4126,4128,4141],{"className":4127},[46],[43,4129,4131],{"className":4130},[50],[52,4132,4133],{"xmlns":54},[56,4134,4135,4139],{},[59,4136,4137],{},[65,4138,72],{},[108,4140,72],{"encoding":110},[43,4142,4144],{"className":4143,"ariaHidden":76},[115],[43,4145,4147,4150],{"className":4146},[119],[43,4148],{"className":4149,"style":297},[123],[43,4151,72],{"className":4152,"style":173},[128,132],": o preço sobe de 300 pra 500 (subiu 200) enquanto o tamanho sobe de 1.0 pra 2.0 (andou 1.0). Inclinação é \"quanto subiu dividido por quanto andou\".",[265,4155,4156,4187,4188,4216,4217,4296,4297,1581],{},[18,4157,4158,4159],{},"O intercepto ",[43,4160,4162,4175],{"className":4161},[46],[43,4163,4165],{"className":4164},[50],[52,4166,4167],{"xmlns":54},[56,4168,4169,4173],{},[59,4170,4171],{},[65,4172,80],{},[108,4174,80],{"encoding":110},[43,4176,4178],{"className":4177,"ariaHidden":76},[115],[43,4179,4181,4184],{"className":4180},[119],[43,4182],{"className":4183,"style":252},[123],[43,4185,80],{"className":4186},[128,132],": já sabendo ",[43,4189,4191,4204],{"className":4190},[46],[43,4192,4194],{"className":4193},[50],[52,4195,4196],{"xmlns":54},[56,4197,4198,4202],{},[59,4199,4200],{},[65,4201,72],{},[108,4203,72],{"encoding":110},[43,4205,4207],{"className":4206,"ariaHidden":76},[115],[43,4208,4210,4213],{"className":4209},[119],[43,4211],{"className":4212,"style":297},[123],[43,4214,72],{"className":4215,"style":173},[128,132],", pega um dos pontos, joga na equação ",[43,4218,4220,4244],{"className":4219},[46],[43,4221,4223],{"className":4222},[50],[52,4224,4225],{"xmlns":54},[56,4226,4227,4241],{},[59,4228,4229,4231,4233,4235,4237,4239],{},[65,4230,646],{},[74,4232,93],{},[65,4234,72],{},[65,4236,87],{},[74,4238,104],{},[65,4240,80],{},[108,4242,4243],{"encoding":110},"y = wx + b",[43,4245,4247,4266,4287],{"className":4246,"ariaHidden":76},[115],[43,4248,4250,4254,4257,4260,4263],{"className":4249},[119],[43,4251],{"className":4252,"style":4253},[123],"height:0.625em;vertical-align:-0.1944em;",[43,4255,646],{"className":4256,"style":797},[128,132],[43,4258],{"className":4259,"style":210},[209],[43,4261,93],{"className":4262},[214],[43,4264],{"className":4265,"style":210},[209],[43,4267,4269,4272,4275,4278,4281,4284],{"className":4268},[119],[43,4270],{"className":4271,"style":224},[123],[43,4273,72],{"className":4274,"style":173},[128,132],[43,4276,87],{"className":4277},[128,132],[43,4279],{"className":4280,"style":238},[209],[43,4282,104],{"className":4283},[242],[43,4285],{"className":4286,"style":238},[209],[43,4288,4290,4293],{"className":4289},[119],[43,4291],{"className":4292,"style":252},[123],[43,4294,80],{"className":4295},[128,132]," e isola o ",[43,4298,4300,4313],{"className":4299},[46],[43,4301,4303],{"className":4302},[50],[52,4304,4305],{"xmlns":54},[56,4306,4307,4311],{},[59,4308,4309],{},[65,4310,80],{},[108,4312,80],{"encoding":110},[43,4314,4316],{"className":4315,"ariaHidden":76},[115],[43,4317,4319,4322],{"className":4318},[119],[43,4320],{"className":4321,"style":252},[123],[43,4323,80],{"className":4324},[128,132],[4326,4327],"model-playground",{":initial-b":4025,":initial-w":4025,":x-train":3086,":y-train":3087,"dataLabel":4328,"error-label":4329,"prediction-label":4330,"success-message":4331,"x-label":3089,"y-label":3090},"Valores reais","Erro total","Sua previsão","Boa! Erro zero, essa reta passa exatamente pelos dois pontos.",[4333,4334,4335,4342,4345,4833,4836,5100],"details",{},[4336,4337,4338,4341],"summary",{},[80,4339,4340],{},"Travou? Aqui vai a conta"," (clique pra revelar)",[14,4343,4344],{},"Inclinação:",[14,4346,4347],{},[43,4348,4350,4451],{"className":4349},[46],[43,4351,4353],{"className":4352},[50],[52,4354,4355],{"xmlns":54},[56,4356,4357,4448],{},[59,4358,4359,4361,4363,4423,4425,4443,4445],{},[65,4360,72],{},[74,4362,93],{},[4364,4365,4366,4395],"mfrac",{},[59,4367,4368,4380,4383],{},[689,4369,4370,4372],{},[65,4371,646],{},[59,4373,4374,4376,4378],{},[74,4375,84],{"stretchy":83},[1284,4377,1546],{},[74,4379,90],{"stretchy":83},[74,4381,4382],{},"−",[689,4384,4385,4387],{},[65,4386,646],{},[59,4388,4389,4391,4393],{},[74,4390,84],{"stretchy":83},[1284,4392,1803],{},[74,4394,90],{"stretchy":83},[59,4396,4397,4409,4411],{},[689,4398,4399,4401],{},[65,4400,87],{},[59,4402,4403,4405,4407],{},[74,4404,84],{"stretchy":83},[1284,4406,1546],{},[74,4408,90],{"stretchy":83},[74,4410,4382],{},[689,4412,4413,4415],{},[65,4414,87],{},[59,4416,4417,4419,4421],{},[74,4418,84],{"stretchy":83},[1284,4420,1803],{},[74,4422,90],{"stretchy":83},[74,4424,93],{},[4364,4426,4427,4435],{},[59,4428,4429,4431,4433],{},[1284,4430,1819],{},[74,4432,4382],{},[1284,4434,1809],{},[59,4436,4437,4439,4441],{},[1284,4438,1816],{},[74,4440,4382],{},[1284,4442,1806],{},[74,4444,93],{},[1284,4446,4447],{},"200",[108,4449,4450],{"encoding":110},"w = \\frac{y^{(1)} - y^{(0)}}{x^{(1)} - x^{(0)}} = \\frac{500 - 300}{2.0 - 1.0} = 200",[43,4452,4454,4472,4724,4824],{"className":4453,"ariaHidden":76},[115],[43,4455,4457,4460,4463,4466,4469],{"className":4456},[119],[43,4458],{"className":4459,"style":297},[123],[43,4461,72],{"className":4462,"style":173},[128,132],[43,4464],{"className":4465,"style":210},[209],[43,4467,93],{"className":4468},[214],[43,4470],{"className":4471,"style":210},[209],[43,4473,4475,4479,4715,4718,4721],{"className":4474},[119],[43,4476],{"className":4477,"style":4478},[123],"height:1.5666em;vertical-align:-0.4438em;",[43,4480,4482,4486,4712],{"className":4481},[128],[43,4483],{"className":4484},[198,4485],"nulldelimiter",[43,4487,4489],{"className":4488},[4364],[43,4490,4492,4703],{"className":4491},[141,142],[43,4493,4495,4700],{"className":4494},[146],[43,4496,4499,4596,4607],{"className":4497,"style":4498},[150],"height:1.1228em;",[43,4500,4502,4506],{"style":4501},"top:-2.6146em;",[43,4503],{"className":4504,"style":4505},[158],"height:3em;",[43,4507,4509],{"className":4508},[163,164,165,166],[43,4510,4512,4555,4558],{"className":4511},[128,166],[43,4513,4515,4518],{"className":4514},[128,166],[43,4516,87],{"className":4517},[128,132,166],[43,4519,4521],{"className":4520},[137],[43,4522,4524],{"className":4523},[141],[43,4525,4527],{"className":4526},[146],[43,4528,4531],{"className":4529,"style":4530},[150],"height:0.822em;",[43,4532,4534,4538],{"style":4533},"top:-2.822em;margin-right:0.0714em;",[43,4535],{"className":4536,"style":4537},[158],"height:2.5357em;",[43,4539,4543],{"className":4540},[163,4541,4542,166],"reset-size3","size1",[43,4544,4546,4549,4552],{"className":4545},[128,166],[43,4547,84],{"className":4548},[198,166],[43,4550,1546],{"className":4551},[128,166],[43,4553,90],{"className":4554},[205,166],[43,4556,4382],{"className":4557},[242,166],[43,4559,4561,4564],{"className":4560},[128,166],[43,4562,87],{"className":4563},[128,132,166],[43,4565,4567],{"className":4566},[137],[43,4568,4570],{"className":4569},[141],[43,4571,4573],{"className":4572},[146],[43,4574,4576],{"className":4575,"style":4530},[150],[43,4577,4578,4581],{"style":4533},[43,4579],{"className":4580,"style":4537},[158],[43,4582,4584],{"className":4583},[163,4541,4542,166],[43,4585,4587,4590,4593],{"className":4586},[128,166],[43,4588,84],{"className":4589},[198,166],[43,4591,1803],{"className":4592},[128,166],[43,4594,90],{"className":4595},[205,166],[43,4597,4599,4602],{"style":4598},"top:-3.23em;",[43,4600],{"className":4601,"style":4505},[158],[43,4603],{"className":4604,"style":4606},[4605],"frac-line","border-bottom-width:0.04em;",[43,4608,4610,4613],{"style":4609},"top:-3.4461em;",[43,4611],{"className":4612,"style":4505},[158],[43,4614,4616],{"className":4615},[163,164,165,166],[43,4617,4619,4659,4662],{"className":4618},[128,166],[43,4620,4622,4625],{"className":4621},[128,166],[43,4623,646],{"className":4624,"style":797},[128,132,166],[43,4626,4628],{"className":4627},[137],[43,4629,4631],{"className":4630},[141],[43,4632,4634],{"className":4633},[146],[43,4635,4638],{"className":4636,"style":4637},[150],"height:0.9667em;",[43,4639,4641,4644],{"style":4640},"top:-2.9667em;margin-right:0.0714em;",[43,4642],{"className":4643,"style":4537},[158],[43,4645,4647],{"className":4646},[163,4541,4542,166],[43,4648,4650,4653,4656],{"className":4649},[128,166],[43,4651,84],{"className":4652},[198,166],[43,4654,1546],{"className":4655},[128,166],[43,4657,90],{"className":4658},[205,166],[43,4660,4382],{"className":4661},[242,166],[43,4663,4665,4668],{"className":4664},[128,166],[43,4666,646],{"className":4667,"style":797},[128,132,166],[43,4669,4671],{"className":4670},[137],[43,4672,4674],{"className":4673},[141],[43,4675,4677],{"className":4676},[146],[43,4678,4680],{"className":4679,"style":4637},[150],[43,4681,4682,4685],{"style":4640},[43,4683],{"className":4684,"style":4537},[158],[43,4686,4688],{"className":4687},[163,4541,4542,166],[43,4689,4691,4694,4697],{"className":4690},[128,166],[43,4692,84],{"className":4693},[198,166],[43,4695,1803],{"className":4696},[128,166],[43,4698,90],{"className":4699},[205,166],[43,4701,185],{"className":4702},[184],[43,4704,4706],{"className":4705},[146],[43,4707,4710],{"className":4708,"style":4709},[150],"height:0.4438em;",[43,4711],{},[43,4713],{"className":4714},[205,4485],[43,4716],{"className":4717,"style":210},[209],[43,4719,93],{"className":4720},[214],[43,4722],{"className":4723,"style":210},[209],[43,4725,4727,4731,4815,4818,4821],{"className":4726},[119],[43,4728],{"className":4729,"style":4730},[123],"height:1.2484em;vertical-align:-0.4033em;",[43,4732,4734,4737,4812],{"className":4733},[128],[43,4735],{"className":4736},[198,4485],[43,4738,4740],{"className":4739},[4364],[43,4741,4743,4803],{"className":4742},[141,142],[43,4744,4746,4800],{"className":4745},[146],[43,4747,4750,4771,4779],{"className":4748,"style":4749},[150],"height:0.8451em;",[43,4751,4753,4756],{"style":4752},"top:-2.655em;",[43,4754],{"className":4755,"style":4505},[158],[43,4757,4759],{"className":4758},[163,164,165,166],[43,4760,4762,4765,4768],{"className":4761},[128,166],[43,4763,1816],{"className":4764},[128,166],[43,4766,4382],{"className":4767},[242,166],[43,4769,1806],{"className":4770},[128,166],[43,4772,4773,4776],{"style":4598},[43,4774],{"className":4775,"style":4505},[158],[43,4777],{"className":4778,"style":4606},[4605],[43,4780,4782,4785],{"style":4781},"top:-3.394em;",[43,4783],{"className":4784,"style":4505},[158],[43,4786,4788],{"className":4787},[163,164,165,166],[43,4789,4791,4794,4797],{"className":4790},[128,166],[43,4792,1819],{"className":4793},[128,166],[43,4795,4382],{"className":4796},[242,166],[43,4798,1809],{"className":4799},[128,166],[43,4801,185],{"className":4802},[184],[43,4804,4806],{"className":4805},[146],[43,4807,4810],{"className":4808,"style":4809},[150],"height:0.4033em;",[43,4811],{},[43,4813],{"className":4814},[205,4485],[43,4816],{"className":4817,"style":210},[209],[43,4819,93],{"className":4820},[214],[43,4822],{"className":4823,"style":210},[209],[43,4825,4827,4830],{"className":4826},[119],[43,4828],{"className":4829,"style":1577},[123],[43,4831,4447],{"className":4832},[128],[14,4834,4835],{},"Intercepto, usando o primeiro ponto:",[14,4837,4838],{},[43,4839,4841,4903],{"className":4840},[46],[43,4842,4844],{"className":4843},[50],[52,4845,4846],{"xmlns":54},[56,4847,4848,4900],{},[59,4849,4850,4852,4854,4866,4868,4870,4872,4884,4886,4888,4890,4892,4894,4896,4898],{},[65,4851,80],{},[74,4853,93],{},[689,4855,4856,4858],{},[65,4857,646],{},[59,4859,4860,4862,4864],{},[74,4861,84],{"stretchy":83},[1284,4863,1803],{},[74,4865,90],{"stretchy":83},[74,4867,4382],{},[65,4869,72],{},[97,4871,99],{},[689,4873,4874,4876],{},[65,4875,87],{},[59,4877,4878,4880,4882],{},[74,4879,84],{"stretchy":83},[1284,4881,1803],{},[74,4883,90],{"stretchy":83},[74,4885,93],{},[1284,4887,1809],{},[74,4889,4382],{},[1284,4891,4447],{},[74,4893,2571],{},[1284,4895,1806],{},[74,4897,93],{},[1284,4899,4025],{},[108,4901,4902],{"encoding":110},"b = y^{(0)} - w\\,x^{(0)} = 300 - 200 \\times 1.0 = 100",[43,4904,4906,4924,4977,5036,5055,5073,5091],{"className":4905,"ariaHidden":76},[115],[43,4907,4909,4912,4915,4918,4921],{"className":4908},[119],[43,4910],{"className":4911,"style":252},[123],[43,4913,80],{"className":4914},[128,132],[43,4916],{"className":4917,"style":210},[209],[43,4919,93],{"className":4920},[214],[43,4922],{"className":4923,"style":210},[209],[43,4925,4927,4930,4968,4971,4974],{"className":4926},[119],[43,4928],{"className":4929,"style":790},[123],[43,4931,4933,4936],{"className":4932},[128],[43,4934,646],{"className":4935,"style":797},[128,132],[43,4937,4939],{"className":4938},[137],[43,4940,4942],{"className":4941},[141],[43,4943,4945],{"className":4944},[146],[43,4946,4948],{"className":4947,"style":714},[150],[43,4949,4950,4953],{"style":735},[43,4951],{"className":4952,"style":159},[158],[43,4954,4956],{"className":4955},[163,164,165,166],[43,4957,4959,4962,4965],{"className":4958},[128,166],[43,4960,84],{"className":4961},[198,166],[43,4963,1803],{"className":4964},[128,166],[43,4966,90],{"className":4967},[205,166],[43,4969],{"className":4970,"style":238},[209],[43,4972,4382],{"className":4973},[242],[43,4975],{"className":4976,"style":238},[209],[43,4978,4980,4983,4986,4989,5027,5030,5033],{"className":4979},[119],[43,4981],{"className":4982,"style":714},[123],[43,4984,72],{"className":4985,"style":173},[128,132],[43,4987],{"className":4988,"style":231},[209],[43,4990,4992,4995],{"className":4991},[128],[43,4993,87],{"className":4994},[128,132],[43,4996,4998],{"className":4997},[137],[43,4999,5001],{"className":5000},[141],[43,5002,5004],{"className":5003},[146],[43,5005,5007],{"className":5006,"style":714},[150],[43,5008,5009,5012],{"style":735},[43,5010],{"className":5011,"style":159},[158],[43,5013,5015],{"className":5014},[163,164,165,166],[43,5016,5018,5021,5024],{"className":5017},[128,166],[43,5019,84],{"className":5020},[198,166],[43,5022,1803],{"className":5023},[128,166],[43,5025,90],{"className":5026},[205,166],[43,5028],{"className":5029,"style":210},[209],[43,5031,93],{"className":5032},[214],[43,5034],{"className":5035,"style":210},[209],[43,5037,5039,5043,5046,5049,5052],{"className":5038},[119],[43,5040],{"className":5041,"style":5042},[123],"height:0.7278em;vertical-align:-0.0833em;",[43,5044,1809],{"className":5045},[128],[43,5047],{"className":5048,"style":238},[209],[43,5050,4382],{"className":5051},[242],[43,5053],{"className":5054,"style":238},[209],[43,5056,5058,5061,5064,5067,5070],{"className":5057},[119],[43,5059],{"className":5060,"style":5042},[123],[43,5062,4447],{"className":5063},[128],[43,5065],{"className":5066,"style":238},[209],[43,5068,2571],{"className":5069},[242],[43,5071],{"className":5072,"style":238},[209],[43,5074,5076,5079,5082,5085,5088],{"className":5075},[119],[43,5077],{"className":5078,"style":1577},[123],[43,5080,1806],{"className":5081},[128],[43,5083],{"className":5084,"style":210},[209],[43,5086,93],{"className":5087},[214],[43,5089],{"className":5090,"style":210},[209],[43,5092,5094,5097],{"className":5093},[119],[43,5095],{"className":5096,"style":1577},[123],[43,5098,4025],{"className":5099},[128],[14,5101,5102,5103,467,5154,5205],{},"Então: ",[43,5104,5106,5124],{"className":5105},[46],[43,5107,5109],{"className":5108},[50],[52,5110,5111],{"xmlns":54},[56,5112,5113,5121],{},[59,5114,5115,5117,5119],{},[65,5116,72],{},[74,5118,93],{},[1284,5120,4447],{},[108,5122,5123],{"encoding":110},"w = 200",[43,5125,5127,5145],{"className":5126,"ariaHidden":76},[115],[43,5128,5130,5133,5136,5139,5142],{"className":5129},[119],[43,5131],{"className":5132,"style":297},[123],[43,5134,72],{"className":5135,"style":173},[128,132],[43,5137],{"className":5138,"style":210},[209],[43,5140,93],{"className":5141},[214],[43,5143],{"className":5144,"style":210},[209],[43,5146,5148,5151],{"className":5147},[119],[43,5149],{"className":5150,"style":1577},[123],[43,5152,4447],{"className":5153},[128],[43,5155,5157,5175],{"className":5156},[46],[43,5158,5160],{"className":5159},[50],[52,5161,5162],{"xmlns":54},[56,5163,5164,5172],{},[59,5165,5166,5168,5170],{},[65,5167,80],{},[74,5169,93],{},[1284,5171,4025],{},[108,5173,5174],{"encoding":110},"b = 100",[43,5176,5178,5196],{"className":5177,"ariaHidden":76},[115],[43,5179,5181,5184,5187,5190,5193],{"className":5180},[119],[43,5182],{"className":5183,"style":252},[123],[43,5185,80],{"className":5186},[128,132],[43,5188],{"className":5189,"style":210},[209],[43,5191,93],{"className":5192},[214],[43,5194],{"className":5195,"style":210},[209],[43,5197,5199,5202],{"className":5198},[119],[43,5200],{"className":5201,"style":1577},[123],[43,5203,4025],{"className":5204},[128],". Bota isso nos sliders lá em cima e confere o erro zerando.",[14,5207,5208,5209,471,5237,5265,5266,5269],{},"Beleza, você achou ",[43,5210,5212,5225],{"className":5211},[46],[43,5213,5215],{"className":5214},[50],[52,5216,5217],{"xmlns":54},[56,5218,5219,5223],{},[59,5220,5221],{},[65,5222,72],{},[108,5224,72],{"encoding":110},[43,5226,5228],{"className":5227,"ariaHidden":76},[115],[43,5229,5231,5234],{"className":5230},[119],[43,5232],{"className":5233,"style":297},[123],[43,5235,72],{"className":5236,"style":173},[128,132],[43,5238,5240,5253],{"className":5239},[46],[43,5241,5243],{"className":5242},[50],[52,5244,5245],{"xmlns":54},[56,5246,5247,5251],{},[59,5248,5249],{},[65,5250,80],{},[108,5252,80],{"encoding":110},[43,5254,5256],{"className":5255,"ariaHidden":76},[115],[43,5257,5259,5262],{"className":5258},[119],[43,5260],{"className":5261,"style":252},[123],[43,5263,80],{"className":5264},[128,132]," na mão, mas repara: você só conseguiu porque tinha ",[18,5267,5268],{},"exatamente 2 pontos e 2 parâmetros pra ajustar",", então dava pra resolver com álgebra de ensino médio. Bota mais dados reais (com ruído, tipo casas parecidas vendendo por preços um pouco diferentes) e nenhuma reta única vai passar por todo mundo, não vai ter \"erro zero\" possível.",[14,5271,5272,5273,5276,5277,5329,5330,467,5332,5391,5392,5395,5396,5447,5448,5450,5451,5454],{},"Aí surge uma pergunta nova: ",[18,5274,5275],{},"qual reta é a \"menos errada\"?"," Eu precisei de um jeito de medir \"o quão errada\" uma reta é, de forma numérica, comparável entre diferentes ",[43,5278,5280,5302],{"className":5279},[46],[43,5281,5283],{"className":5282},[50],[52,5284,5285],{"xmlns":54},[56,5286,5287,5299],{},[59,5288,5289,5291,5293,5295,5297],{},[74,5290,84],{"stretchy":83},[65,5292,72],{},[74,5294,77],{"separator":76},[65,5296,80],{},[74,5298,90],{"stretchy":83},[108,5300,5301],{"encoding":110},"(w,b)",[43,5303,5305],{"className":5304,"ariaHidden":76},[115],[43,5306,5308,5311,5314,5317,5320,5323,5326],{"className":5307},[119],[43,5309],{"className":5310,"style":2049},[123],[43,5312,84],{"className":5313},[198],[43,5315,72],{"className":5316,"style":173},[128,132],[43,5318,77],{"className":5319},[177],[43,5321],{"className":5322,"style":231},[209],[43,5324,80],{"className":5325},[128,132],[43,5327,90],{"className":5328},[205],". Isso é a ",[18,5331,3802],{},[43,5333,5335,5360],{"className":5334},[46],[43,5336,5338],{"className":5337},[50],[52,5339,5340],{"xmlns":54},[56,5341,5342,5357],{},[59,5343,5344,5347,5349,5351,5353,5355],{},[65,5345,5346],{},"J",[74,5348,84],{"stretchy":83},[65,5350,72],{},[74,5352,77],{"separator":76},[65,5354,80],{},[74,5356,90],{"stretchy":83},[108,5358,5359],{"encoding":110},"J(w,b)",[43,5361,5363],{"className":5362,"ariaHidden":76},[115],[43,5364,5366,5369,5373,5376,5379,5382,5385,5388],{"className":5365},[119],[43,5367],{"className":5368,"style":2049},[123],[43,5370,5346],{"className":5371,"style":5372},[128,132],"margin-right:0.0962em;",[43,5374,84],{"className":5375},[198],[43,5377,72],{"className":5378,"style":173},[128,132],[43,5380,77],{"className":5381},[177],[43,5383],{"className":5384,"style":231},[209],[43,5386,80],{"className":5387},[128,132],[43,5389,90],{"className":5390},[205]," (o \"Erro total\" que você viu no playground é uma versão simplificada dela). E eu precisei de um jeito de ",[2334,5393,5394],{},"buscar"," automaticamente o ",[43,5397,5399,5420],{"className":5398},[46],[43,5400,5402],{"className":5401},[50],[52,5403,5404],{"xmlns":54},[56,5405,5406,5418],{},[59,5407,5408,5410,5412,5414,5416],{},[74,5409,84],{"stretchy":83},[65,5411,72],{},[74,5413,77],{"separator":76},[65,5415,80],{},[74,5417,90],{"stretchy":83},[108,5419,5301],{"encoding":110},[43,5421,5423],{"className":5422,"ariaHidden":76},[115],[43,5424,5426,5429,5432,5435,5438,5441,5444],{"className":5425},[119],[43,5427],{"className":5428,"style":2049},[123],[43,5430,84],{"className":5431},[198],[43,5433,72],{"className":5434,"style":173},[128,132],[43,5436,77],{"className":5437},[177],[43,5439],{"className":5440,"style":231},[209],[43,5442,80],{"className":5443},[128,132],[43,5445,90],{"className":5446},[205]," que minimiza esse erro, sem você ficar arrastando slider a vida inteira. Isso é o ",[18,5449,3806],{},": imagina que você tá vendado no topo de uma ladeira e seu único jeito de descer é sentir com o pé qual direção desce mais rápido e dar um passo. Repete isso um monte de vezes e, se tudo der certo, você chega lá embaixo, no ponto de menor erro. É basicamente isso que o ",[525,5452,5453],{"href":3805},"próximo post"," vai destrinchar.",[257,5456,5458],{"id":5457},"fazendo-a-previsão-que-a-gente-queria-desde-o-início","Fazendo a previsão que a gente queria desde o início",[14,5460,5461,467,5511,5561,5562],{},[43,5462,5464,5481],{"className":5463},[46],[43,5465,5467],{"className":5466},[50],[52,5468,5469],{"xmlns":54},[56,5470,5471,5479],{},[59,5472,5473,5475,5477],{},[65,5474,72],{},[74,5476,93],{},[1284,5478,4447],{},[108,5480,5123],{"encoding":110},[43,5482,5484,5502],{"className":5483,"ariaHidden":76},[115],[43,5485,5487,5490,5493,5496,5499],{"className":5486},[119],[43,5488],{"className":5489,"style":297},[123],[43,5491,72],{"className":5492,"style":173},[128,132],[43,5494],{"className":5495,"style":210},[209],[43,5497,93],{"className":5498},[214],[43,5500],{"className":5501,"style":210},[209],[43,5503,5505,5508],{"className":5504},[119],[43,5506],{"className":5507,"style":1577},[123],[43,5509,4447],{"className":5510},[128],[43,5512,5514,5531],{"className":5513},[46],[43,5515,5517],{"className":5516},[50],[52,5518,5519],{"xmlns":54},[56,5520,5521,5529],{},[59,5522,5523,5525,5527],{},[65,5524,80],{},[74,5526,93],{},[1284,5528,4025],{},[108,5530,5174],{"encoding":110},[43,5532,5534,5552],{"className":5533,"ariaHidden":76},[115],[43,5535,5537,5540,5543,5546,5549],{"className":5536},[119],[43,5538],{"className":5539,"style":252},[123],[43,5541,80],{"className":5542},[128,132],[43,5544],{"className":5545,"style":210},[209],[43,5547,93],{"className":5548},[214],[43,5550],{"className":5551,"style":210},[209],[43,5553,5555,5558],{"className":5554},[119],[43,5556],{"className":5557,"style":1577},[123],[43,5559,4025],{"className":5560},[128]," ajustados. Agora sim: ",[18,5563,5564],{},"quanto vale a casa de 1200 pés²?",[14,5566,5567,5568,1581],{},"Lembrando a escala: 1200 pés² é ",[43,5569,5571,5590],{"className":5570},[46],[43,5572,5574],{"className":5573},[50],[52,5575,5576],{"xmlns":54},[56,5577,5578,5587],{},[59,5579,5580,5582,5584],{},[65,5581,87],{},[74,5583,93],{},[1284,5585,5586],{},"1.2",[108,5588,5589],{"encoding":110},"x = 1.2",[43,5591,5593,5611],{"className":5592,"ariaHidden":76},[115],[43,5594,5596,5599,5602,5605,5608],{"className":5595},[119],[43,5597],{"className":5598,"style":297},[123],[43,5600,87],{"className":5601},[128,132],[43,5603],{"className":5604,"style":210},[209],[43,5606,93],{"className":5607},[214],[43,5609],{"className":5610,"style":210},[209],[43,5612,5614,5617],{"className":5613},[119],[43,5615],{"className":5616,"style":1577},[123],[43,5618,5586],{"className":5619},[128],[14,5621,5622],{},[43,5623,5625,5672],{"className":5624},[46],[43,5626,5628],{"className":5627},[50],[52,5629,5630],{"xmlns":54},[56,5631,5632,5669],{},[59,5633,5634,5646,5648,5650,5652,5654,5656,5658,5660,5662,5664,5666],{},[62,5635,5636,5638],{},[65,5637,67],{},[59,5639,5640,5642,5644],{},[65,5641,72],{},[74,5643,77],{"separator":76},[65,5645,80],{},[74,5647,84],{"stretchy":83},[1284,5649,5586],{},[74,5651,90],{"stretchy":83},[74,5653,93],{},[1284,5655,4447],{},[74,5657,2571],{},[1284,5659,5586],{},[74,5661,104],{},[1284,5663,4025],{},[74,5665,93],{},[1284,5667,5668],{},"340",[108,5670,5671],{"encoding":110},"f_{w,b}(1.2) = 200 \\times 1.2 + 100 = 340",[43,5673,5675,5748,5766,5784,5802],{"className":5674,"ariaHidden":76},[115],[43,5676,5678,5681,5730,5733,5736,5739,5742,5745],{"className":5677},[119],[43,5679],{"className":5680,"style":124},[123],[43,5682,5684,5687],{"className":5683},[128],[43,5685,67],{"className":5686,"style":133},[128,132],[43,5688,5690],{"className":5689},[137],[43,5691,5693,5722],{"className":5692},[141,142],[43,5694,5696,5719],{"className":5695},[146],[43,5697,5699],{"className":5698,"style":151},[150],[43,5700,5701,5704],{"style":154},[43,5702],{"className":5703,"style":159},[158],[43,5705,5707],{"className":5706},[163,164,165,166],[43,5708,5710,5713,5716],{"className":5709},[128,166],[43,5711,72],{"className":5712,"style":173},[128,132,166],[43,5714,77],{"className":5715},[177,166],[43,5717,80],{"className":5718},[128,132,166],[43,5720,185],{"className":5721},[184],[43,5723,5725],{"className":5724},[146],[43,5726,5728],{"className":5727,"style":192},[150],[43,5729],{},[43,5731,84],{"className":5732},[198],[43,5734,5586],{"className":5735},[128],[43,5737,90],{"className":5738},[205],[43,5740],{"className":5741,"style":210},[209],[43,5743,93],{"className":5744},[214],[43,5746],{"className":5747,"style":210},[209],[43,5749,5751,5754,5757,5760,5763],{"className":5750},[119],[43,5752],{"className":5753,"style":5042},[123],[43,5755,4447],{"className":5756},[128],[43,5758],{"className":5759,"style":238},[209],[43,5761,2571],{"className":5762},[242],[43,5764],{"className":5765,"style":238},[209],[43,5767,5769,5772,5775,5778,5781],{"className":5768},[119],[43,5770],{"className":5771,"style":5042},[123],[43,5773,5586],{"className":5774},[128],[43,5776],{"className":5777,"style":238},[209],[43,5779,104],{"className":5780},[242],[43,5782],{"className":5783,"style":238},[209],[43,5785,5787,5790,5793,5796,5799],{"className":5786},[119],[43,5788],{"className":5789,"style":1577},[123],[43,5791,4025],{"className":5792},[128],[43,5794],{"className":5795,"style":210},[209],[43,5797,93],{"className":5798},[214],[43,5800],{"className":5801,"style":210},[209],[43,5803,5805,5808],{"className":5804},[119],[43,5806],{"className":5807,"style":1577},[123],[43,5809,5668],{"className":5810},[128],[14,5812,5813,5814,1581],{},"340, na escala do problema, é ",[18,5815,5816],{},"340 mil dólares",[2344,5818,5820],{"className":2346,"code":5819,"language":2348,"meta":2349,"style":2349},"w = 200      # Peso ajustado (achado no desafio).\nb = 100      # Viés ajustado (achado no desafio).\n\nx_i = 1.2    # Entrada nova: 1200 pés² = 1.2, porque x está em milhares de pés².\n\ncost_1200sqft = w * x_i + b     # Aplica o modelo. Não confundir com \"função de custo\", nome parecido, coisa diferente.\n\nprint(f\"${cost_1200sqft:.0f} mil dólares\")\n",[33,5821,5822,5827,5832,5836,5841,5845,5850,5854],{"__ignoreMap":2349},[43,5823,5824],{"class":2354,"line":2355},[43,5825,5826],{},"w = 200      # Peso ajustado (achado no desafio).\n",[43,5828,5829],{"class":2354,"line":2361},[43,5830,5831],{},"b = 100      # Viés ajustado (achado no desafio).\n",[43,5833,5834],{"class":2354,"line":2367},[43,5835,2394],{"emptyLinePlaceholder":2393},[43,5837,5838],{"class":2354,"line":2372},[43,5839,5840],{},"x_i = 1.2    # Entrada nova: 1200 pés² = 1.2, porque x está em milhares de pés².\n",[43,5842,5843],{"class":2354,"line":2378},[43,5844,2394],{"emptyLinePlaceholder":2393},[43,5846,5847],{"class":2354,"line":2384},[43,5848,5849],{},"cost_1200sqft = w * x_i + b     # Aplica o modelo. Não confundir com \"função de custo\", nome parecido, coisa diferente.\n",[43,5851,5852],{"class":2354,"line":2390},[43,5853,2394],{"emptyLinePlaceholder":2393},[43,5855,5856],{"class":2354,"line":2397},[43,5857,5858],{},"print(f\"${cost_1200sqft:.0f} mil dólares\")\n",[11,5860,5861],{},[14,5862,5863,1254,5865],{},[18,5864,2430],{},[33,5866,5867],{},"$340 mil dólares",[14,5869,5870,5871,1254,5921,5924,5925,5928],{},"Presta atenção no que rolou aqui: ",[43,5872,5874,5891],{"className":5873},[46],[43,5875,5877],{"className":5876},[50],[52,5878,5879],{"xmlns":54},[56,5880,5881,5889],{},[59,5882,5883,5885,5887],{},[65,5884,87],{},[74,5886,93],{},[1284,5888,5586],{},[108,5890,5589],{"encoding":110},[43,5892,5894,5912],{"className":5893,"ariaHidden":76},[115],[43,5895,5897,5900,5903,5906,5909],{"className":5896},[119],[43,5898],{"className":5899,"style":297},[123],[43,5901,87],{"className":5902},[128,132],[43,5904],{"className":5905,"style":210},[209],[43,5907,93],{"className":5908},[214],[43,5910],{"className":5911,"style":210},[209],[43,5913,5915,5918],{"className":5914},[119],[43,5916],{"className":5917,"style":1577},[123],[43,5919,5586],{"className":5920},[128],[18,5922,5923],{},"nunca apareceu"," nos dados de treino. A gente só tinha casas de 1.0 e 2.0. O modelo generalizou pra um caso que ele nunca viu, e é exatamente por isso que a gente treina modelo, não é pra decorar os 2 pontos que já sabíamos (isso qualquer print de tabela faz). É pra prever o que a gente ",[18,5926,5927],{},"não"," sabe.",[257,5930,5932],{"id":5931},"fechando","Fechando",[484,5934,5935,5948],{},[487,5936,5937],{},[490,5938,5939,5942,5945],{},[493,5940,5941],{"align":495},"Etapa",[493,5943,5944],{"align":495},"O que rolou",[493,5946,5947],{"align":495},"Código-chave",[504,5949,5950,5965,5983,5996,6160,6230],{},[490,5951,5952,5957,5960],{},[509,5953,5954],{"align":495},[18,5955,5956],{},"1. Dados",[509,5958,5959],{"align":495},"representar os exemplos como arrays NumPy",[509,5961,5962],{"align":495},[33,5963,5964],{},"np.array([...])",[490,5966,5967,5972,5975],{},[509,5968,5969],{"align":495},[18,5970,5971],{},"2. Inspeção",[509,5973,5974],{"align":495},"contar exemplos e pescar um exemplo específico",[509,5976,5977,467,5980],{"align":495},[33,5978,5979],{},".shape[0]",[33,5981,5982],{},"x_train[i]",[490,5984,5985,5990,5993],{},[509,5986,5987],{"align":495},[18,5988,5989],{},"3. Visualização",[509,5991,5992],{"align":495},"olhar os dados antes de modelar",[509,5994,5995],{"align":495},"gráfico interativo",[490,5997,5998,6003,6155],{},[509,5999,6000],{"align":495},[18,6001,6002],{},"4. Modelo",[509,6004,6005,6006,6154],{"align":495},"definir ",[43,6007,6009,6048],{"className":6008},[46],[43,6010,6012],{"className":6011},[50],[52,6013,6014],{"xmlns":54},[56,6015,6016,6046],{},[59,6017,6018,6030,6032,6034,6036,6038,6040,6042,6044],{},[62,6019,6020,6022],{},[65,6021,67],{},[59,6023,6024,6026,6028],{},[65,6025,72],{},[74,6027,77],{"separator":76},[65,6029,80],{},[74,6031,84],{"stretchy":83},[65,6033,87],{},[74,6035,90],{"stretchy":83},[74,6037,93],{},[65,6039,72],{},[65,6041,87],{},[74,6043,104],{},[65,6045,80],{},[108,6047,350],{"encoding":110},[43,6049,6051,6124,6145],{"className":6050,"ariaHidden":76},[115],[43,6052,6054,6057,6106,6109,6112,6115,6118,6121],{"className":6053},[119],[43,6055],{"className":6056,"style":124},[123],[43,6058,6060,6063],{"className":6059},[128],[43,6061,67],{"className":6062,"style":133},[128,132],[43,6064,6066],{"className":6065},[137],[43,6067,6069,6098],{"className":6068},[141,142],[43,6070,6072,6095],{"className":6071},[146],[43,6073,6075],{"className":6074,"style":151},[150],[43,6076,6077,6080],{"style":154},[43,6078],{"className":6079,"style":159},[158],[43,6081,6083],{"className":6082},[163,164,165,166],[43,6084,6086,6089,6092],{"className":6085},[128,166],[43,6087,72],{"className":6088,"style":173},[128,132,166],[43,6090,77],{"className":6091},[177,166],[43,6093,80],{"className":6094},[128,132,166],[43,6096,185],{"className":6097},[184],[43,6099,6101],{"className":6100},[146],[43,6102,6104],{"className":6103,"style":192},[150],[43,6105],{},[43,6107,84],{"className":6108},[198],[43,6110,87],{"className":6111},[128,132],[43,6113,90],{"className":6114},[205],[43,6116],{"className":6117,"style":210},[209],[43,6119,93],{"className":6120},[214],[43,6122],{"className":6123,"style":210},[209],[43,6125,6127,6130,6133,6136,6139,6142],{"className":6126},[119],[43,6128],{"className":6129,"style":224},[123],[43,6131,72],{"className":6132,"style":173},[128,132],[43,6134,87],{"className":6135},[128,132],[43,6137],{"className":6138,"style":238},[209],[43,6140,104],{"className":6141},[242],[43,6143],{"className":6144,"style":238},[209],[43,6146,6148,6151],{"className":6147},[119],[43,6149],{"className":6150,"style":252},[123],[43,6152,80],{"className":6153},[128,132]," e implementar",[509,6156,6157],{"align":495},[33,6158,6159],{},"compute_model_output()",[490,6161,6162,6167,6227],{},[509,6163,6164],{"align":495},[18,6165,6166],{},"5. Parâmetros",[509,6168,6169,6170,471,6198,6226],{"align":495},"achar ",[43,6171,6173,6186],{"className":6172},[46],[43,6174,6176],{"className":6175},[50],[52,6177,6178],{"xmlns":54},[56,6179,6180,6184],{},[59,6181,6182],{},[65,6183,72],{},[108,6185,72],{"encoding":110},[43,6187,6189],{"className":6188,"ariaHidden":76},[115],[43,6190,6192,6195],{"className":6191},[119],[43,6193],{"className":6194,"style":297},[123],[43,6196,72],{"className":6197,"style":173},[128,132],[43,6199,6201,6214],{"className":6200},[46],[43,6202,6204],{"className":6203},[50],[52,6205,6206],{"xmlns":54},[56,6207,6208,6212],{},[59,6209,6210],{},[65,6211,80],{},[108,6213,80],{"encoding":110},[43,6215,6217],{"className":6216,"ariaHidden":76},[115],[43,6218,6220,6223],{"className":6219},[119],[43,6221],{"className":6222,"style":252},[123],[43,6224,80],{"className":6225},[128,132]," na mão, mexendo até o erro zerar",[509,6228,6229],{"align":495},"playground interativo",[490,6231,6232,6237,6240],{},[509,6233,6234],{"align":495},[18,6235,6236],{},"6. Previsão",[509,6238,6239],{"align":495},"aplicar o modelo pra um dado novo",[509,6241,6242],{"align":495},[33,6243,6244],{},"w * x_i + b",[14,6246,6247],{},"Três ideias pra levar:",[262,6249,6250,6264,6327],{},[265,6251,6252,6255,6256,6259,6260,6263],{},[18,6253,6254],{},"Regressão linear modela uma relação"," entre uma entrada (",[2334,6257,6258],{},"feature",") e uma saída (",[2334,6261,6262],{},"target","). Aqui: tamanho → preço. Amanhã pode ser qualquer outra coisa: km rodado → preço da corrida, tamanho do arquivo → tempo de processamento, sei lá.",[265,6265,6266,6269,6270,471,6298,6326],{},[18,6267,6268],{},"O modelo só tem dois botões",": ",[43,6271,6273,6286],{"className":6272},[46],[43,6274,6276],{"className":6275},[50],[52,6277,6278],{"xmlns":54},[56,6279,6280,6284],{},[59,6281,6282],{},[65,6283,72],{},[108,6285,72],{"encoding":110},[43,6287,6289],{"className":6288,"ariaHidden":76},[115],[43,6290,6292,6295],{"className":6291},[119],[43,6293],{"className":6294,"style":297},[123],[43,6296,72],{"className":6297,"style":173},[128,132],[43,6299,6301,6314],{"className":6300},[46],[43,6302,6304],{"className":6303},[50],[52,6305,6306],{"xmlns":54},[56,6307,6308,6312],{},[59,6309,6310],{},[65,6311,80],{},[108,6313,80],{"encoding":110},[43,6315,6317],{"className":6316,"ariaHidden":76},[115],[43,6318,6320,6323],{"className":6319},[119],[43,6321],{"className":6322,"style":252},[123],[43,6324,80],{"className":6325},[128,132],". É só isso que muda quando o modelo \"aprende\". Não tem mágica escondida.",[265,6328,6329,6332],{},[18,6330,6331],{},"O ponto todo é generalizar",": prever coisa que o modelo nunca viu. Se ele só reproduzisse os dados de treino, seria uma tabela disfarçada, não um modelo.",[14,6334,6335,6340,6341,6392,6393,6449,6450,6452],{},[18,6336,6337,3510],{},[525,6338,6339],{"href":3801},"No próximo post"," você achou ",[43,6342,6344,6365],{"className":6343},[46],[43,6345,6347],{"className":6346},[50],[52,6348,6349],{"xmlns":54},[56,6350,6351,6363],{},[59,6352,6353,6355,6357,6359,6361],{},[74,6354,84],{"stretchy":83},[65,6356,72],{},[74,6358,77],{"separator":76},[65,6360,80],{},[74,6362,90],{"stretchy":83},[108,6364,5301],{"encoding":110},[43,6366,6368],{"className":6367,"ariaHidden":76},[115],[43,6369,6371,6374,6377,6380,6383,6386,6389],{"className":6370},[119],[43,6372],{"className":6373,"style":2049},[123],[43,6375,84],{"className":6376},[198],[43,6378,72],{"className":6379,"style":173},[128,132],[43,6381,77],{"className":6382},[177],[43,6384],{"className":6385,"style":231},[209],[43,6387,80],{"className":6388},[128,132],[43,6390,90],{"className":6391},[205]," arrastando slider porque tinha só 2 pontos. Isso não escala pra dados de verdade. A gente formaliza a função de custo ",[43,6394,6396,6419],{"className":6395},[46],[43,6397,6399],{"className":6398},[50],[52,6400,6401],{"xmlns":54},[56,6402,6403,6417],{},[59,6404,6405,6407,6409,6411,6413,6415],{},[65,6406,5346],{},[74,6408,84],{"stretchy":83},[65,6410,72],{},[74,6412,77],{"separator":76},[65,6414,80],{},[74,6416,90],{"stretchy":83},[108,6418,5359],{"encoding":110},[43,6420,6422],{"className":6421,"ariaHidden":76},[115],[43,6423,6425,6428,6431,6434,6437,6440,6443,6446],{"className":6424},[119],[43,6426],{"className":6427,"style":2049},[123],[43,6429,5346],{"className":6430,"style":5372},[128,132],[43,6432,84],{"className":6433},[198],[43,6435,72],{"className":6436,"style":173},[128,132],[43,6438,77],{"className":6439},[177],[43,6441],{"className":6442,"style":231},[209],[43,6444,80],{"className":6445},[128,132],[43,6447,90],{"className":6448},[205],", a \"nota\" que mede o quão ruim uma reta é, e começa a preparar o terreno pro ",[525,6451,3806],{"href":3805},", que é quem vai fazer essa busca por você, automaticamente, em dados que não cabem mais numa conta de cabeça.",[257,6454,6456],{"id":6455},"aplicação-prática","Aplicação prática",[14,6458,6459,6460,6466],{},"Chega de dado de brinquedo. Vamos aplicar exatamente o que você aprendeu aqui num dataset real de imóveis: 500 casas, com tamanho, número de quartos, distância do centro e preço de verdade (",[525,6461,6465],{"href":6462,"rel":6463},"https:\u002F\u002Fwww.kaggle.com\u002Fdatasets\u002Fdenkuznetz\u002Fhousing-prices-regression",[6464],"nofollow","Housing Prices Regression, Kaggle","). Sem conceito novo, só o que esse post já ensinou, agora em cima de dado com ruído de verdade.",[2339,6468,6470],{"id":6469},"explorando-as-features","Explorando as features",[2344,6472,6474],{"className":2346,"code":6473,"language":2348,"meta":2349,"style":2349},"import pandas as pd\n\ndf = pd.read_csv(\"real_estate_dataset.csv\")\n\nprint(df[[\"Square_Feet\", \"Num_Bedrooms\", \"Location_Score\", \"Distance_to_Center\", \"Price\"]].describe())\n\nprint(df.corr(numeric_only=True)[\"Price\"].sort_values(ascending=False))\n",[33,6475,6476,6481,6485,6490,6494,6499,6503],{"__ignoreMap":2349},[43,6477,6478],{"class":2354,"line":2355},[43,6479,6480],{},"import pandas as pd\n",[43,6482,6483],{"class":2354,"line":2361},[43,6484,2394],{"emptyLinePlaceholder":2393},[43,6486,6487],{"class":2354,"line":2367},[43,6488,6489],{},"df = pd.read_csv(\"real_estate_dataset.csv\")\n",[43,6491,6492],{"class":2354,"line":2372},[43,6493,2394],{"emptyLinePlaceholder":2393},[43,6495,6496],{"class":2354,"line":2378},[43,6497,6498],{},"print(df[[\"Square_Feet\", \"Num_Bedrooms\", \"Location_Score\", \"Distance_to_Center\", \"Price\"]].describe())\n",[43,6500,6501],{"class":2354,"line":2384},[43,6502,2394],{"emptyLinePlaceholder":2393},[43,6504,6505],{"class":2354,"line":2390},[43,6506,6507],{},"print(df.corr(numeric_only=True)[\"Price\"].sort_values(ascending=False))\n",[11,6509,6510],{},[14,6511,6512,1254,6515,467,6518,467,6521,467,6524,1581],{},[18,6513,6514],{},"Saída (correlação com o preço):",[33,6516,6517],{},"Square_Feet 0.65",[33,6519,6520],{},"Num_Bedrooms 0.57",[33,6522,6523],{},"Distance_to_Center 0.26",[33,6525,6526],{},"Location_Score 0.05",[14,6528,6529,6532],{},[33,6530,6531],{},"Square_Feet"," é de longe a feature que mais anda junto com o preço aqui. Bate com a história que a gente contou o post inteiro: tamanho da casa é o ponto de partida certo.",[2339,6534,6536],{"id":6535},"a-matriz-de-features-em-3d","A \"matriz de features\" em 3D",[14,6538,6539],{},"Antes de reduzir pra uma variável só, girei as três dimensões que mais importam ao mesmo tempo: tamanho, quartos e preço.",[6541,6542],"housing-scatter3d",{},[14,6544,6545],{},"Repara como a altura (preço) sobe visivelmente junto com o tamanho, mais do que junto com o número de quartos. É a mesma correlação de cima, só que agora você tá vendo com os próprios olhos em vez de ler um número.",[2339,6547,6549,6550,471,6578,6606],{"id":6548},"achando-www-e-bbb-na-mão-com-dado-de-verdade","Achando ",[43,6551,6553,6566],{"className":6552},[46],[43,6554,6556],{"className":6555},[50],[52,6557,6558],{"xmlns":54},[56,6559,6560,6564],{},[59,6561,6562],{},[65,6563,72],{},[108,6565,72],{"encoding":110},[43,6567,6569],{"className":6568,"ariaHidden":76},[115],[43,6570,6572,6575],{"className":6571},[119],[43,6573],{"className":6574,"style":297},[123],[43,6576,72],{"className":6577,"style":173},[128,132],[43,6579,6581,6594],{"className":6580},[46],[43,6582,6584],{"className":6583},[50],[52,6585,6586],{"xmlns":54},[56,6587,6588,6592],{},[59,6589,6590],{},[65,6591,80],{},[108,6593,80],{"encoding":110},[43,6595,6597],{"className":6596,"ariaHidden":76},[115],[43,6598,6600,6603],{"className":6599},[119],[43,6601],{"className":6602,"style":252},[123],[43,6604,80],{"className":6605},[128,132]," na mão, com dado de verdade",[14,6608,6609],{},"Mesmo playground do post, mesma mecânica, só que agora com as 50 casas reais no lugar dos 2 pontos perfeitos:",[6611,6612],"housing-model-playground",{},[14,6614,6615,6616,6619],{},"Repara que dessa vez o erro ",[18,6617,6618],{},"não zera",", por mais que você mexa nos sliders. Isso não é bug, é o que o próximo post inteiro vai explicar: com dado real e ruidoso, não existe reta perfeita, só a \"menos errada\".",[2339,6621,6623],{"id":6622},"prevendo-o-preço-de-uma-casa-nova","Prevendo o preço de uma casa nova",[2344,6625,6627],{"className":2346,"code":6626,"language":2348,"meta":2349,"style":2349},"# Usando o ajuste aproximado que achamos brincando com o playground:\nw = 116      # dólares (em milhares) a mais por cada 100 pés² de tamanho\nb = 399      # preço-base, em milhares de dólares\n\ncasa_nova = 220 \u002F 100     # 220 pés², na mesma escala do gráfico\n\npreco_previsto = w * casa_nova + b   # em milhares de dólares\n\nprint(f\"${preco_previsto * 1000:,.0f} dólares\")\n",[33,6628,6629,6634,6639,6644,6648,6653,6657,6662,6666],{"__ignoreMap":2349},[43,6630,6631],{"class":2354,"line":2355},[43,6632,6633],{},"# Usando o ajuste aproximado que achamos brincando com o playground:\n",[43,6635,6636],{"class":2354,"line":2361},[43,6637,6638],{},"w = 116      # dólares (em milhares) a mais por cada 100 pés² de tamanho\n",[43,6640,6641],{"class":2354,"line":2367},[43,6642,6643],{},"b = 399      # preço-base, em milhares de dólares\n",[43,6645,6646],{"class":2354,"line":2372},[43,6647,2394],{"emptyLinePlaceholder":2393},[43,6649,6650],{"class":2354,"line":2378},[43,6651,6652],{},"casa_nova = 220 \u002F 100     # 220 pés², na mesma escala do gráfico\n",[43,6654,6655],{"class":2354,"line":2384},[43,6656,2394],{"emptyLinePlaceholder":2393},[43,6658,6659],{"class":2354,"line":2390},[43,6660,6661],{},"preco_previsto = w * casa_nova + b   # em milhares de dólares\n",[43,6663,6664],{"class":2354,"line":2397},[43,6665,2394],{"emptyLinePlaceholder":2393},[43,6667,6668],{"class":2354,"line":2403},[43,6669,6670],{},"print(f\"${preco_previsto * 1000:,.0f} dólares\")\n",[11,6672,6673],{},[14,6674,6675,1254,6677],{},[18,6676,2430],{},[33,6678,6679],{},"$654,200 dólares",[14,6681,6682],{},"Mesma conta do post, mesma fórmula, só que agora validada em cima de um dataset que você (ou qualquer leitor) pode baixar e conferir.",[6684,6685,6686],"style",{},"html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}",{"title":2349,"searchDepth":2361,"depth":2361,"links":6688},[6689,6690,6691,6697,6698,6701,6702,6703,6704],{"id":259,"depth":2361,"text":260},{"id":478,"depth":2361,"text":479},{"id":1584,"depth":2361,"text":1585,"children":6692},[6693,6694,6696],{"id":2341,"depth":2367,"text":2342},{"id":2475,"depth":2367,"text":6695},"Quantos exemplos eu tenho? (mmm)",{"id":2621,"depth":2367,"text":2622},{"id":3078,"depth":2361,"text":3079},{"id":3096,"depth":2361,"text":3097,"children":6699},[6700],{"id":3814,"depth":2367,"text":3815},{"id":3934,"depth":2361,"text":3935},{"id":5457,"depth":2361,"text":5458},{"id":5931,"depth":2361,"text":5932},{"id":6455,"depth":2361,"text":6456,"children":6705},[6706,6707,6708,6710],{"id":6469,"depth":2367,"text":6470},{"id":6535,"depth":2367,"text":6536},{"id":6548,"depth":2367,"text":6709},"Achando www e bbb na mão, com dado de verdade",{"id":6622,"depth":2367,"text":6623},null,"2026-08-18","O modelo mais simples de Machine Learning que existe, f(x) = wx + b, esmiuçado: por que reta, o que w e b significam de verdade, e por que 'achar os parâmetros na mão' não escala.","md",{},"\u002Fpt\u002Fplaylists\u002Fmachine-learning-specialization\u002Flab02-model-representation","machine-learning-specialization",{"title":6,"description":6713},"published","pt\u002Fplaylists\u002Fmachine-learning-specialization\u002Flab02-model-representation",[6722,6723,6724],"regressao-linear","numpy","fundamentos","EwkXe6NO3aQW160jhdQDA0aJTJeokP8g-ZnXHn38inU",1787338983069]