OpenSolver 2.5.3 alpha (2 Jul 2014)

In this release we are adding support for the NOMAD non-linear solver in 64-bit Office. Differences between the 32 and 64-bit versions of Office previously caused NOMAD to crash in 64-bit Office, but these issues have been identified and resolved now.

For anyone that might run into a similar problem in the future, the problem was our use of Application.Run to access the NOMAD DLL:

Application.Run("NomadMain", SolveRelaxation)

When Application.Run was used like this on 64-bit Office, any C API calls from the DLL back into Excel would fail. Instead, the function must be called directly and everything then works fine:

NomadMain(SolveRelaxation)

You can get it here. Let us know how NOMAD goes in 64-bit Office, and we welcome any other feedback too!