exercise1-lihao

Untitled12.m

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+clear
+clc
+%������ ����������ݡ�  200������  ÿ������2������
+data=1*rand(300,2);
+label=zeros(300,1);
+%label(sqrt(data(:,1).^2+data(:,2).^2)<8)=1;
+label((data(:,2)+data(:,1)>1))=1;
+%��data�ϼӳ��������
+data=[data,ones(size(data,1),1)];
+%����ѭ��
+randIndex = randperm(size(data,1));
+data_new=data(randIndex,:);
+label_new=label(randIndex,:);
+%80%ѵ��  20%����
+k=0.8*size(data,1);
+X1=data_new(1:k,:);
+Y1=label_new(1:k,:);
+X2=data_new(k+1:end,:);
+Y2=label_new(k+1:end,:);
+[m1,n1] = size(X1);
+[m2,n2] = size(X2);
+Features=size(data,2); %��������
+%�趨ѧϰ��Ϊ0.01
+delta=1;  
+lamda=0.2; %������ϵ��
+theta1=rand(1,Features); 
+%�ݶ��½��㷨���theta
+num = 300; %����������
+L=[];
+while(num)
+    dt=zeros(1,Features);
+    loss=0;
+    for i=1:m1
+        xx=X1(i,1:Features);
+        yy=Y1(i,1);
+        h=1/(1+exp(-(theta1 * xx')));
+        dt=dt+(h-yy) * xx;
+        loss=loss+ yy*log(h)+(1-yy)*log(1-h);
+    end
+    loss=-loss/m1;
+    L=[L,loss];
+
+    theta2=theta1 - delta*dt/m1 - lamda*theta1/m1;
+    theta1=theta2;
+    num = num - 1;
+
+    if loss<0.01
+        break;
+    end
+end
+figure
+subplot(1,2,1)
+plot(L)
+title('loss')
+subplot(1,2,2)
+x=0:0.1:10;
+y=(-theta1(1)*x-theta1(3))/theta1(2);
+plot(x,y,'linewidth',2)
+hold on
+plot(data(label==1,1),data(label==1,2),'ro')
+hold on
+plot(data(label==0,1),data(label==0,2),'go')
+axis([0 1 0 1])
+%��������
+acc=0;
+for i=1:m2
+    xx=X2(i,1:Features)';
+    yy=Y2(i);
+    finil=1/(1+exp(-theta2 * xx));
+    if finil>0.5 && yy==1
+        acc=acc+1;
+    end
+    if finil<=0.5 && yy==0
+        acc=acc+1;
+    end
+end
+acc/m2