Pyomo 6.9.4

Highlights of the 6.9 release series

• Removed support for Python 3.8
• New Logic-Based Discrete-Steepest Descent Algorithm in GDPOpt
• New External Function for Cubic Spline Interpolation
• New ASL External Functions Library
• New solver interfaces:
  • Support for upcoming knitro Python package
  • v2: Ongoing solver interface refactor
• ...and of course numerous minor bug fixes and performance enhancements

Changes in this release

• General
  • Cleanup collections module (#3708)
  • Work around environments where IntEnum.__doc__ is None (#3711)
  • Standardize 'multiprocessing' deferred import (#3702)
  • Resolve capture_output(capture_fd=True) deadlock on Windows (#3679)
• Core
  • Bugfix: standard form with fixed variables (#3704)
• DAE
  • Fix simulator bug (#3692)
• Solver Interfaces
  • Add reporting of SCIP node count to solver results (#3691)
  • Create API version attribute for different solver generations (#3699)
  • Ipopt_v2: update options processing (#3693)
  • Expanded LegacySolverWrapper fixes (#3700)
• Testing
  • Update GAMS download to new "latest" link (#3706)
  • New TPL cache version on GHA workflows (#3705)
• Contributed Packages
  • benders: Added support for HiGHS solver (#3686)
  • DoE: Add grey box objectives (#3606)
  • Parmest: Correct two very old test skips (#3697)
  • Parmest: Extend capability for weighted SSE objective (#3535)
  • PyROS: Modify two solver tests (#3694)
  • sensitivity_toolbox: Sensitivity calculation for named expressions (#3685)