Hi @Toine,
Thank you very much for your suggestions, we will try this!
Kind regards,
Eline
Hi @ElineOoms,
A quick follow up: Currently, CPLEX Barrier crossover is disabled for your model. You could try enabling crossover:
Settings > Project options > Specific solvers > CPLEX > General > Solution type = Automatic or Basic
Barrier crossover is disabled if the Solution type is set to Non-basic.
Best regards,
Toine
Hi @ElineOoms,
Enabling the AIMMS scaling tool could be a solution to your problem. This tool is designed eliminate numerical instabilities in your mathematical program.
You can enable this tool by going to:
Settings > Project options > Solvers general > Scaling > Scale model
There you can also find more information about the scaling tool, by going to 'Help'.
Additionally, there is a post about the scaling tool on the Community: https://community.aimms.com/what-s-new-at-aimms-26/marcel-hunting-on-the-aimms-scaling-tool-718
Best regards,
Toine
Hi @Marcel Hunting,
Thank you for the suggestions. I put the logging on (for a run with other inputs, however this run also ends up in intermediate non-optimal) and this is the file I get. It states:
A solution is available, but not proved optimal, due to numeric difficulties during optimization with CPLEX.
A solution is available, but not proved optimal, due to numeric difficulties during the optimization.
How can I avoid these numeric difficulties?
Hi @ElineOoms To find out what it means you should enable CPLEX logging by setting the following options:
- Solvers General option 'Solver listing messages' to 'All'
- CPLEX option 'Barrier display' to 'Normal' or ‘Diagnostics’
If you then rerun the model, CPLEX will create a status file in the log folder. If you need help with understanding this status file then please copy it here.