When using IPOPT the derivative_test_perturbation and derivative_test_tol seems to be always set to the same value.
I think the issue come from this line :
https://github.com/FreeFem/FreeFem-sources/blob/master/plugin/seq/ff-Ipopt.cpp#L1475
which should be
"GetAny< double >((nargs[17])(stack)));"
instead of
"GetAny< double >((nargs[16])(stack)));".
When using IPOPT the derivative_test_perturbation and derivative_test_tol seems to be always set to the same value. I think the issue come from this line : https://github.com/FreeFem/FreeFem-sources/blob/master/plugin/seq/ff-Ipopt.cpp#L1475 which should be "GetAny< double >((nargs[17])(stack)));" instead of "GetAny< double >((nargs[16])(stack)));".