Undefined function 'sigmoid' for input arguments of type 'double'.

addpath('C:\Program Files\MATLAB\R2012a\Matlab\q2')

load X.dat

load Y.dat

temp1=X(:,1);

temp2=X(:,2);

temp1=(temp1-mean(temp1))./std(temp1);

temp2=(temp2-mean(temp2))./std(temp2);

m=length(X);

X=[ones(m,1),temp1,temp2];

theta=[0;0;0];

MAX_ITR=100;

J=zeros(MAX_ITR,1);

alpha=0.07;

for num_iteration=1:MAX_ITR

J(num_iteration)=(1/m)*((-Y')*log(sigmoid(X*theta))-(1-Y')*log(1-sigmoid(X*theta)));

grad=(1/m)*X'*(sigmoid(X*theta)-Y);

theta=theta-alpha.*grad;

end

z=X*theta;

g=inline('(1./(1+exp(-z)))');

fprintf('Theta values are ...\n')

g(z)

Undefined function 'sigmoid' for input arguments of type 'double'.

Answer 1

[Guillaume]

As far as I can tell, sigmoid is not a function of matlab in any toolbox, so unless you've written it yourself and it's in the matlab path, it's not going to be found.