exactly, i need the hermitian adjoint of the convolution-operation c, say c^H The reason is that I am considering a functional F(x) = 1/2*||cx -y||_2^2, where c is just a simple conv.layer with no activation function. Considering the derivative of F with respect to x I get c^H(cx -y). Thus, I need the adjoint operator of c. Since a conv. can in general be associated with a linear operator (i.e. a matrix), if I had the matrix as it was, it would be easy, cause I would just use A^H. But I would like to be able to express the operation A^H by means of the same function which I am using in the implementation, i.e conv2d or conv3d. I guess using FFT in that case does not help, since in the end I end up with c^H(cx -y) anyway.
But thanks again