我正在使用 matlab 实现多层神经网络。在我代表的代码中
每个节点的值 AS netValue{k}
第 k 层和第 k 层之间的权重 + 1 AS权重{k}
等等
由于这些数据是三维的,因此我必须使用单元格来保存二维矩阵以启用矩阵乘法。
所以训练模型变得非常慢,我预计这是由于使用了单元格造成的。
谁能告诉我如何加速这段代码?谢谢
clc;
close all;
clear all;
input = [-2 : 0.4 : 2;-2:0.4:2];
ican = 4;
depth = 4; % total layer - 1, by convension
[featureNum , sampleNum] = size(input);
levelNum(1) = featureNum;
levelNum(2) = 5;
levelNum(3) = 5;
levelNum(4) = 5;
levelNum(5) = 2;
weight = cell(0);
for k = 1 : depth
weight{k} = rand(levelNum(k+1), levelNum(k)) - 2 * rand(levelNum(k+1) , levelNum(k));
threshold{k} = rand(levelNum(k+1) , 1) - 2 * rand(levelNum(k+1) , 1);
end
runCount = 0;
sumMSE = 1; % init MSE
minError = 1e-5;
afa = 0.1; % step of "gradient ascendence"
% training loop
while(runCount < 100000 & sumMSE > minError)
sumMSE = 0; % sum of MSE
for i = 1 : sampleNum % sample loop
netValue{1} = input(:,i);
for k = 2 : depth
netValue{k} = weight{k-1} * netValue{k-1} + threshold{k-1}; %calculate each layer
netValue{k} = 1 ./ (1 + exp(-netValue{k})); %apply logistic function
end
netValue{depth+1} = weight{depth} * netValue{depth} + threshold{depth}; %output layer
e = 1 + sin((pi / 4) * ican * netValue{1}) - netValue{depth + 1}; %calc error
assistS{depth} = diag(ones(size(netValue{depth+1})));
s{depth} = -2 * assistS{depth} * e;
for k = depth - 1 : -1 : 1
assistS{k} = diag((1-netValue{k+1}).*netValue{k+1});
s{k} = assistS{k} * weight{k+1}' * s{k+1};
end
for k = 1 : depth
weight{k} = weight{k} - afa * s{k} * netValue{k}';
threshold{k} = threshold{k} - afa * s{k};
end
sumMSE = sumMSE + e' * e;
end
sumMSE = sqrt(sumMSE) / sampleNum;
runCount = runCount + 1;
end
x = [-2 : 0.1 : 2;-2:0.1:2];
y = zeros(size(x));
z = 1 + sin((pi / 4) * ican .* x);
% test
for i = 1 : length(x)
netValue{1} = x(:,i);
for k = 2 : depth
netValue{k} = weight{k-1} * netValue{k-1} + threshold{k-1};
netValue{k} = 1 ./ ( 1 + exp(-netValue{k}));
end
y(:, i) = weight{depth} * netValue{depth} + threshold{depth};
end
plot(x(1,:) , y(1,:) , 'r');
hold on;
plot(x(1,:) , z(1,:) , 'g');
hold off;