Commercial version of IPOPT
Starting with 23.8 GAMS offers a commercially supported version of GAMS/IPOPT. This version of GAMS/IPOPT offers in addition the commercial strength linear solvers MA27, MA57, and MA86 from the
Harwell Subroutine Library (HSL).
We will continue to include IPOPT without the HSL routines free of charge in the Base module.
With 24.0, GAMS changed the scheme on how to use IPOPT with HSL routines.
IPOPT is now always the open source version that uses MUMPS as linear solver and is included in the Base module.
IPOPTH is the commercially supported version that uses the HSL routines. For IPOPTH, an additional license is required.
Analogously, BONMIN is included in the base module and uses IPOPT with MUMPS as NLP solver.
BONMINH uses IPOPT with HSL routines as NLP solver and requires a license for IPOPTH.
For Couenne and SCIP, IPOPTH is used to solve NLP subproblems if an IPOPTH license is available, otherwise IPOPT is used.
To summarize, we suggest to use solvers in the following way:
| without IPOPTH license | with IPOPTH license |
Ipopt | NLP=IPOPT | NLP=IPOPTH |
Bonmin | MINLP=BONMIN | MINLP=BONMINH |
Couenne | (MI)NLP=COUENNE | (MI)NLP=COUENNE |
SCIP | (MI)NLP=SCIP | (MI)NLP=SCIP |