神经网络算法在地球物理中应用综述.doc

神经网络作业第一题取学习速度为0.04clear all;clc;p1=[1;1];p2=[1;2];p3=[2;-1];p4=[2;0];p5=[-1;2];p6=[-2;1];p7=[-1;-1];p8=[-2;-2];t1=[-1;-1];t2=[-1;-1];t3=[-1;1];t4=[-1;1];t5=[1;-1];t6=[1;-1];t7=[1;1];t8=[1;1];w=[1,0;0,1]; b=[1;1]; alpha=0.04;for i=1:8 a=w*p1+b; e=t1-a; w=w+2*alpha*p1*e; b=b+2*alpha*e;endplot([-1,-2],[-1,-2],bx);hold on;plot([-1,-2],[2,1],go);hold on;plot([2,2],[-1,0],c*);hold on;plot([1,1],[1,2],k+);hold on;x=-3:0.1:3;y1=(-b(1)-w(1,1)*x)/w(1,2);y2=(-b(2)-w(2,1)*x)/w(2,2);plot(x,y1,m,x,y2,m)axis([-3,3,-3,3]);legend( 1, 2, 3, 4);第二题clear all;clc;P = [0,1,0,1;0,0,1,1];P = [ones(1,4);P];d = [0,0,0,1];w = [0,0,0];lr = maxlinlr(P);max = 200;for i = 1:maxv = w*P;y = v;yy = y=0.5;e = d-y;m(i) = mse(e);dw = lr*e*P;w = w+dw;endplot([0,1,0],[0,0,1],b*);hold on;plot(1,1,g+);x = -2:0.2:2;y = 1.5-x;plot(x,y);axis([-0.5,2,-0.5,2]);title(“与”逻辑);legend(0,1);第四题通过计算确定搜索区间为0—0.8clc;clear all;a0=0;a2=0.8;a1=(a0+a2)/2;%确定初始搜索区间fa0=f(a0);fa1=f(a1);fa2=f(a2);%通过子函数计算函数值a3=((a1^2-a2^2)*fa0+(a2^2-a0^2)*fa1+(a0^2-a1^2)*fa2)/(2*((a1-a2)*fa0+(a2-a0)*fa1+(a0-a1)*fa2));%计算极小值a3a=2;while a0.0001 %判断是否符合精度 fa3=f(a3); %根据a3和f(a3)的值改变减小搜索区间 if a3a1 if fa1fa3 a0=a1;a1=a3; fa0=fa1;fa1=fa3; else a2=a3; fa2=fa3; end else if fa1=fa3 a0=a3; fa0=fa3; else a2=a1;a1=a3; fa2=fa1;fa1=fa3; end end a3=((a1^2-a2^2)*fa0+(a2^2-a0^2)*fa1+(a0^2-a1^2)*fa2)/(2*((a1-a2)*fa0+(a2-a0)*fa1+(a0-a1)*fa2)); a=abs(a3-a1); %计算a3-a1的绝对值enda3fa3经过迭代，当符合精度时，取a3=0.4126时，取得极小值f(a3)=0.1079