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Inconsistent behavior between the CBC and HiGHS #2656
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@SolverMax it would help us debug this if you could provide the full stacktrace of the error you're seeing. I haven't tried running your model but on first glance this seems like a bug, the APPSI HiGHS interface should work on models with mutable parameters without needing to call the For reference for others these are lines 30 and 31 mentioned above:
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When I run the model, the error message is:
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+1 |
This should get fixed by #2763 |
The problem was mutable parameters that resulted in coefficients with a value of 0. We were handing these coefficients to HiGHS so we can efficiently modify them if the mutable parameter value changes, but HiGHS was unhappy with that. It turns out that we can skip these coefficients and still update them efficiently if the mutable parameter value changes. |
I'm puzzled by inconsistent behavior between the CBC and HiGHS solvers.
Given the attached model, CBC returns the correct optimal solution of 15, while HiGHS fails with an error: "ValueError: Error when adding rows". The choice of solver is specified on line 3.
The HiGHS error occurs on line 30. However, if we comment out line 30 and uncomment line 31, then HiGHS works correctly.
When using HiGHS, why is it necessary to use pyo.value(Model.ShelfHeights[s]) rather than just Model.ShelfHeights[s] like we can with CBC (and GLPK)?
Pyomo version 6.4.3
HiGHS version 1.4.0
HiGHS_test.txt
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