test_for_zeros: Test if any matrix element is zero.
Description
Function tests is any matrix element is zero. For those elements
the function sets those values to the minimum value allowed (not zero).
This is used to avoid numerical problems in the FIM calculation.
Usage
test_for_zeros(mat, ourzero)
Arguments
mat
A matrix.
ourzero
A matrix the same size as mat with the value that zero should be reassigned to.