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How to fix the basis after removing non-basic rows.
I am working on an algorithm in which I need to remove some redundant constraints. I know they are redundant because each one is dominated by one other constraint that I have generated. The problem...
Hi,
Assuming you have a valid factorisation at this point, you can ask the optimizer what variable is basic in the row you are removing using XPRSgetpivotorder: https://www.fico.com/fico-xpress-optimization/docs/latest/solver/optimizer/HTML/XPRSgetpivotorder.html
If you do not have a valid factorization (changing the problem after postsolve), to make sure you have a valid factorization may need to call XPRSinvert ('int XPRS_CC XPRSinvert(XPRSprob prob);') before asking for the pivot order. This can be relatively expensive, so please make sure to remove all redundant rows in a single call.
Please le us know if this does not work,
Zsolt Csizmadia