scipopt
How to get ConstraintDual?
The column generation algorithm performs well in the HiGHS Optimizer, but when I switched to the SCIP Optimizer, it returns the following error:
MathOptInterface.GetAttributeNotAllowed{MathOptInterface.ConstraintDual}: Getting attribute MathOptInterface.ConstraintDual(1) cannot be performed: SCIP.Optimizer does not support getting the attribute MathOptInterface.ConstraintDual(1). You may want to use a `CachingOptimizer` in `AUTOMATIC` mode or you may need to call `reset_optimizer` before doing this operation if the `CachingOptimizer` is in `MANUAL` mode.
How can I solve this?
Hi,
Yes indeed, SCIP is not an LP solver and as such, cannot easily return the duals to users even when the problem is linear. To stay in a Julia-based CG algorithm indeed an LP solver like HiGHs will be more suited.
If you want to do column generation within SCIP, there is a part of the documentation on implementing pricers.
On Sun, Feb 4, 2024, 14:26 Klaixiya @.***> wrote:
The column generation algorithm performs well in the HiGHS Optimizer, but when I switched to the SCIP Optimizer, it returns the following error:
MathOptInterface.GetAttributeNotAllowed{MathOptInterface.ConstraintDual}: Getting attribute MathOptInterface.ConstraintDual(1) cannot be performed: SCIP.Optimizer does not support getting the attribute MathOptInterface.ConstraintDual(1). You may want to use a
CachingOptimizerinAUTOMATICmode or you may need to callreset_optimizerbefore doing this operation if theCachingOptimizeris inMANUALmode.How can I solve this?
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