在训练迭代期间测试精度降低

时间:2017-08-10 07:04:35

标签: machine-learning neural-network biological-neural-network

在我的神经网络模型中,迭代中的测试精度会降低。我已经检查了学习率并将其调整得更小,但我的测试精度不断下降但没有振荡,所以我认为这不是问题的原因。

我使用tempotron学习规则,并使用Iris数据集,我使用了100个训练样本和50个测试样本。

我检查了我的代码,测试准确性在开始时有所增加,所以我认为学习规则对重量有效。

但我无法弄清楚为什么之后性能下降。 有人有什么想法吗? 感谢。

testing accuracy

for Iterate = 1:iteration  %% Run 100 times

  %% Test the correct rate each time

正确= 0;    for test_sample = 1:length(test)

   % In each iteration, T = 100ms

    for t = 1:T                

        for neuron = 1:neurons %% Response function for 48 neurons at time t

                 Response(neuron) = K(t,test(test_sample,neuron));              

        end

        % Calculate PSP

        for j = 1:3                

           V(j,t) = Response*weight(:,j) + V_rest;            

        end           

    end         

    %% find t_max: first index that V cross threshold

    for j = 1:3

        for timing = 1:T

            if V(j,timing) >= threshold

                t_max(j) = timing;

                Max_state(j) = V(j,timing);

                break;

            end

        end     

       V(j,t_max(j):end) = V(j,t_max(j)).*exp(-(Time(t_max(j):end)-Time(t_max(j)))/Tou_m);

    end

    [~,output_class] = min(t_max); 

    if output_class == test_target(test_sample)

        correct = correct + 1;

    end

correct_rate(Iterate)= correct /(length(test));

如果迭代> 1

 if correct_rate(Iterate) < correct_rate(Iterate-1)

     fprintf('Correct rate decrease\n');

     %break;

 end

%%培训

for samples = 1:size(InputSpike,1)  %% Training samples for each iteration 

    % In each iteration, T = 100ms

    for t = 1:T                  

        for neuron = 1:neurons %% Response function for 48 neurons at time t

            Response(neuron) = K(t,InputSpike(samples,neuron));              

        end       

        % Calculate PSP

        for j = 1:3                

           V(j,t) = Response*weight(:,j) + V_rest;            

        end

    end           

    %% find t_max: first index that V cross threshold

    for j = 1:3

        for timing = 1:T

            if V(j,timing) >= threshold

                t_max(j) = timing;

                Max_state(j) = V(j,timing);

                break;

            end

        end        

       V(j,t_max(j):end) = V(j,t_max(j)).*exp(-(Time(t_max(j):end)-
Time(t_max(j)))/Tou_m);

end

    [~,output_class] = min(t_max);

    %% weight modify when error occurs       

    if train_target(samples) ~= output_class        

        for j = 1:3               

            if j == train_target(samples) %% error in target neuron

                if Max_state(j) < threshold %% if P+ error occurs

                    for i = 1:neurons

                        %% for all t_i < t_max

                        if InputSpike(samples,i) < t_max(j) 

                            %% weight modified

                            weight(i,j) = weight(i,j) + ...
                                lr*K(t_max(j),InputSpike(samples,i));

                        end

                    end

                end

            elseif j ~= train_target(samples) %% error on other 2 output neurons  

               if Max_state(j) >= threshold %% if P- error occurs

                   for i = 1:neurons

                        %% for all t_i < t_max

                        if InputSpike(samples,i) < t_max(j) 

                            %% weight modified

                            weight(i,j) = weight(i,j) - ...
                                lr*K(t_max(j),InputSpike(samples,i));

                        end

                   end

               end

            end 

        end     

    %% for neurons that fired but weaker than target neuron     

    elseif train_target(samples) == output_class

        for j = 1:3

            if j ~= train_target(samples) %% other 2 output neurons

                if Max_state(j) >= threshold

                   for i = 1:neurons %% P- error occurs

                        %% for all t_i < t_max

                        if InputSpike(samples,i) < t_max(j) 

                            %% weight modified

                            weight(i,j) = weight(i,j) - ...
                                lr*K(t_max(j),InputSpike(samples,i));

                        end 

                   end

                end

            end

        end

    end         

end    

1 个答案:

答案 0 :(得分:0)

您应该扩大您的训练数据集,以避免过度拟合。您也可以尝试增加训练次数。