VL_NNRELU - CNN rectified linear unit.
Y = VL_NNRELU(X) applies the rectified linear unit to the data X. X can have arbitrary size.
DZDX = VL_NNRELU(X, DZDY) computes the derivative of the block projected onto DZDY. DZDX and DZDY have the same dimensions as X and Y respectively.
VL_NNRELU(...,'OPT',VALUE,...) takes the following options:
Set the leak factor, a non-negative number. Y is equal to X if X is not smaller than zero; otherwise, Y is equal to X multipied by the leak factor. By default, the leak factor is zero; for values greater than that one obtains the leaky ReLU unit.
As a further optimization, in the backward computation it is possible to replace X with Y, namely, if Y = VL_NNRELU(X), then VL_NNRELU(X,DZDY) gives the same result as VL_NNRELU(Y,DZDY). This is useful because it means that the buffer X does not need to be remembered in the backward pass.