MATLAB: Getting error “Undefined function or method ‘logistic’ for input arguments of type ‘double’.””

neural network

I have written a code based on neural network and when I ma trying to run code getting error as "Undefined function or method 'logistic' for input arguments of type 'double'" I have given the portion of code where getting error.
double logistic(x)
    if(x > 100.0)
        x = 1.0;
    else if (x < -100.0) 
            x = 0.0;
    else x = 1.0/(1.0+exp(-x));
     x;
        end
    end
function [V_OUT]= feed_forward_signals(MAT_INOUT, V_IN, V_OUT, V_BIAS, size1, size2, layer)
for row = 1:size2
    V_OUT(row)=0;
    for col = 1:size1
     V_OUT(row)=V_OUT(row)+MAT_INOUT(row,col)*V_IN(col);
    end
      V_OUT(row)=V_OUT(row)+V_BIAS(row);
end
      if(layer==0)
          V_OUT(row) = tanh(V_OUT(row));
      end
      if(layer==1) 
          V_OUT(row) = logistic(V_OUT(row));
please help
      end

Best Answer

If you have the Neural Network Toolbox just use
 LOGSIG or TANSIG
 otherwise, just use TANH.
Also see
Subject: NEURAL NET TRAINING SPEED USING A MODIFIED ELLIOT SIGMOID
From: Greg Heath
Date: 14 Oct, 2012 06:18:08
Hope this helps.
Thank you for formally accepting my answer
Greg
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