bp3.m

这是一个BP神经网络的程序

% BP A invert
% By Ma Shuyan Jue 1,2002
% P=W2*W1*P,W2 is not changed,so W1 is the inverse of W2
% W1=net.IW{1,1}
function bp3()
clear;

load A.dat;
S=spconvert(A);
W2=full(S);
n1=10;
T=eye(n1);
P=T;B2=zeros(10,1);B1=B2;

% Creat an object with two layers,and each layer has 10 neural elements
% inputs are between -1 and 1
% W2,B2 and B1 are not changed,only change W1
net=newff([-1 1;-1 1;-1 1;-1 1;-1 1;-1 1;-1 1;-1 1;-1 1;-1 1],[10,10],{'tansig','purelin'},'traingd');
net.LW{2,1}=W2;net.b{2}=B2;net.b{1}=B1;net.layerWeights{2,1}.learn=0;net.biases{1}.learn=0;
net.biases{2}.learn=0;
net.trainParam.show = 200;
net.trainParam.lr = 0.2;
net.trainParam.epochs = 2000;
net.trainParam.goal = 1e-5;

[net,tr]=train(net,P,T);

a = sim(net,P)
W1=net.IW{1,1}
W1*W2