[Ipopt] MPI Issue in IPOPT 3.11.7 / Mumps

[Dominique Orban]

Hi there,

Building IPOPT 3.11.7 with clang/clang++ or gcc/g++ on OSX 10.8.5 against MUMPS 4.10.0 and OpenMPI 1.7.4 results in the C test hs071_c hanging forever or crashing.

There appears to be a problem with the MPI setup in the Mumps interface. The C test solves the problem twice (the second solve with warm starting). But this means that MPI_Init() is called twice and that leads to an error: https://gist.github.com/dpo/9120810

A user suggested that IPOPT shouldn't call MPI_Init() at all and proposes a patch (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=736842) but applying this patch results in a situation where MPI_Init() is never called:

	The MPI_Comm_f2c() function was called before MPI_INIT was invoked.

Both my C++ and MPI knowledge are extremely limited. Somehow, MPI_Init() is called again when re-solving and/or MPI_Finalize() is never called. Or something else is going on... I got in touch with the Mumps guys to see if they have any advice.

Cheers,

Dominique