Neural Networks: Sigmoid Activation Function for continuous output variable

Question

Okay, so I am in the middle of Andrew Ng\'s machine learning course on coursera and would like to adapt the neural network which was completed as part of assignment 4.

Answer 1

If you want to have continuous output try not to use sigmoid activation when computing target value.

a1 = [ones(m, 1) X];   
a2 = sigmoid(X * Theta1');  
a2 = [ones(m, 1) z1];  
a3 = z1 * Theta2';  
ht = a3;

Normalize input before using it in nnCostFunction. Everything else remains same.