With neural networks, we are working with sets of matrices:
In order to use optimizing functions such as "fminunc()", we will want to "unroll" all the elements and put them into one long vector:
thetaVector = [ Theta1(:); Theta2(:); Theta3(:); ]
deltaVector = [ D1(:); D2(:); D3(:) ]
If the dimensions of Theta1 is 10x11, Theta2 is 10x11 and Theta3 is 1x11, then we can get back our original matrices from the "unrolled" versions as follows:
Theta1 = reshape(thetaVector(1:110),10,11) Theta2 = reshape(thetaVector(111:220),10,11) Theta3 = reshape(thetaVector(221:231),1,11)
