ipopt solver external function that computes the jacobian of the constraints for CUTEr.
cjac = ipopt_grcntr(x)
A vector, the current value of the unknown
A vector, the current value of the non zero elements of the jacobian
This function computes the jacobian of the constraints at the
point x
for the current CUTEr problem
according to the ipopt
requirements.
It includes a cpu time limitation to cancel the resolution if the cpu time exceeds 3600s.