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#?»ñÈ¡Êý¾Ý¼¯?import?numpy?as?np?import?pandas?as?pd?from?sklearn?import?datasets?from?sklearn?import?preprocessing?from?sklearn.model_selection?import?train_test_split?breast?=?datasets.load_breast_cancer()?scaler?=?preprocessing.MinMaxScaler()?data?=?scaler.fit_transform(breast['data'])?target?=?breast['target']?X_train,X_test,y_train,y_test?=?train_test_split(data,target)?

import?numpy?as?np?import?pandas?as?pd?#¶¨Ò弤»îº¯Êý?ReLu?=?lambda?z:np.maximum(0.0,z)?d_ReLu?=?lambda?z:np.where(z<0,0,1)?LeakyReLu?=?lambda?z:np.maximum(0.01*z,z)?d_LeakyReLu?=?lambda?z:np.where(z<0,0.01,1)?Sigmoid?=?lambda?z:1/(1+np.exp(-z))?d_Sigmoid?=?lambda?z:?Sigmoid(z)*(1-Sigmoid(z))?#d_Sigmoid?=?a(1-a)?Tanh?=?np.tanh?d_Tanh?=?lambda?z:1?-?Tanh(z)**2?#d_Tanh?=?1?-?a**2?class?NNClassifier(object):??def?__init__(self,n?=?[np.nan,5,5,1],alpha?=?0.1,ITERNUM?=?50000,?gfunc?=?'ReLu'):??self.n?=?n?#¸÷²ã½ÚµãÊý??self.gfunc?=?gfunc?#Òþ²Ø²ã¼¤»îº¯Êý??self.alpha,self.ITERNUM?=?alpha,ITERNUM??self.dfJ?=?pd.DataFrame(data?=?np.zeros((ITERNUM,1)),columns?=?['J'])??self.W,self.b?=?np.nan,np.nan??#?È·¶¨¸÷²ã¼¤»îº¯Êý??self.g?=?[eval(self.gfunc)?for?i?in?range(len(n))];??self.g[-1]?=?Sigmoid;self.g[0]?=?np.nan??#?È·¶¨Òþ²Ø²ã¼¤»îº¯ÊýµÄµ¼Êý??self.d_gfunc?=?eval('d_'?+?self.gfunc)??def?fit(self,X_train,y_train):??X,Y?=?X_train.T,y_train.reshape(1,-1)??m?=?X.shape[1]?#Ñù±¾¸öÊý??n?=?self.n;?n[0]?=?X.shape[0]?#?¸÷²ã½ÚµãÊýÁ¿??#?½ÚµãÖµºÍ²ÎÊý³õʼ»¯??A?=?[np.zeros((ni,m))?for?ni?in?n];A[0]?=?X?#¸÷²ã½ÚµãÊä³öÖµ³õʼ»¯??Z?=?[np.zeros((ni,m))?for?ni?in?n];Z[0]?=?np.nan?#¸÷²ã½ÚµãÖмäÖµ³õʼ»¯??W?=?[np.nan]?+?[np.random.randn(n[i],n[i-1])?*?0.01?for?i?in?range(1,len(n))]?#¸÷²ãϵÊý²ÎÊý??b?=?[np.zeros((ni,1))?for?ni?in?n];b[0]?=?np.nan?#n¸÷²ãÆ«ÖòÎÊý??#?µ¼Êý³õʼ»¯??dA?=?[np.zeros(Ai.shape)?for?Ai?in?A]??dZ?=?[np.zeros(Ai.shape)?for?Ai?in?A]??dW?=?[np.zeros(Wi.shape)?if?isinstance(Wi,np.ndarray)?else?np.nan?for?Wi?in?W]???db?=?[np.zeros(bi.shape)?if?isinstance(bi,np.ndarray)?else?np.nan?for?bi?in?b]???for?k?in?range(self.ITERNUM):??#?---------ÕýÏò´«²¥?----------??for?i?in?range(1,len(n)):??Z[i]?=?np.dot(W[i],A[i-1])?+?b[i]??A[i]?=?self.g[i](Z[i])??J?=?(1/m)?*?np.sum(-?Y*np.log(A[len(n)-1])?-(1-Y)*np.log(1-A[len(n)-1]))??self.dfJ.loc[k]['J']=?J??#?----------·´Ïò´«²¥?---------??hmax?=?len(n)?-?1??dA[hmax]?=?1/m*(-Y/A[hmax]?+?(1-Y)/(1-A[hmax]))??dZ[hmax]?=?1/m*(A[hmax]-Y)??dW[hmax]?=?np.dot(dZ[hmax],A[hmax-1].T)??db[hmax]?=?np.dot(dZ[hmax],np.ones((m,1)))??for?i?in?range(len(n)-2,0,-1):??dA[i]?=?np.dot(W[i+1].T,dZ[i+1])??dZ[i]?=?dA[i]*?self.d_gfunc(Z[i])??dW[i]?=?np.dot(dZ[i],A[i-1].T)??db[i]?=?np.dot(dZ[i],np.ones((m,1)))??#-----------ÌݶÈϽµ?---------??for?i?in?range(1,len(n)):??W[i]?=?W[i]?-?self.alpha*dW[i]???b[i]?=?b[i]?-?self.alpha*db[i]??#?ÏÔʾ½ø¶È??if?(k+1)%1000?==?0:??print('progress?rate£º{}/{}'.format(k+1,self.ITERNUM),end?=?'\r')??self.W,self.b?=?W,b??def?predict_prob(self,X_test):??#?---------ÕýÏò´«²¥?----------??W,b?=?self.W,self.b??Ai?=?X_test.T??for?i?in?range(1,len(self.n)):??Zi?=?np.dot(W[i],Ai)?+?b[i]??Ai?=?self.g[i](Zi)??return(Ai.reshape(-1))??def?predict(self,X_test):??Y_prob?=?self.predict_prob(X_test)??Y_test?=?Y_prob.copy()??Y_test[Y_prob>=0.5]?=?1??Y_test[Y_prob<?0.5]?=?0??return(Y_test)??

#?²ÉÓÃSigmoid¼¤»îº¯Êý?NN?=?NNClassifier(n?=?[np.nan,5,1],alpha?=?0.02,??ITERNUM?=?200000,?gfunc?=?'Sigmoid')?NN.fit(X_train,y_train)?#?»æÖÆÄ¿±êº¯Êýµü´úÇúÏß?%matplotlib?inline?NN.dfJ.plot(figsize?=?(12,8))?#?²âÊÔÔÚÑéÖ¤¼¯µÄaucµÃ·Ö?from?sklearn.metrics?import?roc_auc_score?Y_prob?=?NN.predict_prob(X_test)?roc_auc_score(list(y_test),list(Y_prob))?

#?²ÉÓÃ?Tanh¼¤»îº¯Êý?NN?=?NNClassifier(n?=?[np.nan,5,1],alpha?=?0.02,??ITERNUM?=?200000,?gfunc?=?'Tanh')?NN.fit(X_train,y_train)?#?»æÖÆÄ¿±êº¯Êýµü´úÇúÏß?%matplotlib?inline?NN.dfJ.plot(figsize?=?(12,8))?#?²âÊÔÔÚÑéÖ¤¼¯µÄaucµÃ·Ö?from?sklearn.metrics?import?roc_auc_score?Y_prob?=?NN.predict_prob(X_test)?roc_auc_score(list(y_test),list(Y_prob))?

#?²ÉÓÃ?ReLu¼¤»îº¯Êý?NN?=?NNClassifier(n?=?[np.nan,5,1],alpha?=?0.02,??ITERNUM?=?200000,?gfunc?=?'ReLu')?NN.fit(X_train,y_train)?#?»æÖÆÄ¿±êº¯Êýµü´úÇúÏß?%matplotlib?inline?NN.dfJ.plot(figsize?=?(12,8))?#?²âÊÔÔÚÑéÖ¤¼¯µÄaucµÃ·Ö?from?sklearn.metrics?import?roc_auc_score?Y_prob?=?NN.predict_prob(X_test)?roc_auc_score(list(y_test),list(Y_prob))?

#?²ÉÓÃ?LeakyReLu¼¤»îº¯Êý?NN?=?NNClassifier(n?=?[np.nan,5,1],alpha?=?0.02,??ITERNUM?=?200000,?gfunc?=?'LeakyReLu')?NN.fit(X_train,y_train)?#?»æÖÆÄ¿±êº¯Êýµü´úÇúÏß?%matplotlib?inline?NN.dfJ.plot(figsize?=?(12,8))?#?²âÊÔÔÚÑéÖ¤¼¯µÄaucµÃ·Ö?from?sklearn.metrics?import?roc_auc_score?Y_prob?=?NN.predict_prob(X_test)?roc_auc_score(list(y_test),list(Y_prob))?

#?ÉèÖÃÁ½¸öÒþ²Ø²ã£¬²ÉÓÃReLu¼¤»îº¯Êý?NN?=?NNClassifier(n?=?[np.nan,5,5,1],alpha?=?0.02,??ITERNUM?=?200000,?gfunc?=?'ReLu')?NN.fit(X_train,y_train)?#?»æÖÆÄ¿±êº¯Êýµü´úÇúÏß?%matplotlib?inline?NN.dfJ.plot(figsize?=?(12,8))?#?²âÊÔÔÚÑéÖ¤¼¯µÄaucµÃ·Ö?from?sklearn.metrics?import?roc_auc_score?Y_prob?=?NN.predict_prob(X_test)?roc_auc_score(list(y_test),list(Y_prob))?

#?Ë«Òþ²Ø²ã£¬Òþ²Ø²ã½ÚµãÊýΪ3?NN?=?NNClassifier(n?=?[np.nan,3,3,1],alpha?=?0.02,??ITERNUM?=?200000,?gfunc?=?'ReLu')?NN.fit(X_train,y_train)?#?»æÖÆÄ¿±êº¯Êýµü´úÇúÏß?%matplotlib?inline?NN.dfJ.plot(figsize?=?(12,8))?#?²âÊÔÔÚÑéÖ¤¼¯µÄaucµÃ·Ö?from?sklearn.metrics?import?roc_auc_score?Y_prob?=?NN.predict_prob(X_test)?roc_auc_score(list(y_test),list(Y_prob))?

#?ºÍsklearnÖеÄÄ£ÐͶԱÈ?from?sklearn.neural_network?import?MLPClassifier?#?µÚÒ»Òþ²Ø²ãÉñ¾­Ôª¸öÊýΪ3£¬µÚ¶þÒþ²Ø²ãÉñ¾­Ôª¸öÊýΪ3?MLPClf?=?MLPClassifier(hidden_layer_sizes=(3,3),max_iter=200000,activation='relu')?MLPClf.fit(X_train,y_train)?#?»æÖÆÄ¿±êº¯Êýµü´úÇúÏß?dfJ?=?pd.DataFrame(data?=?np.array(MLPClf.loss_curve_),columns?=?['J'])?dfJ.plot(figsize?=?(12,8))?#?²âÊÔÔÚÑéÖ¤¼¯µÄaucµÃ·Ö?from?sklearn.metrics?import?roc_auc_score?Y_prob?=?MLPClf.predict_proba(X_test)[:,1]?roc_auc_score(list(y_test),list(Y_prob))?