Can I use Highs just to presolve and postsolve a MIP model?

[linpeng0105]

When I call highs in a C++ environment, can I use highs to presolve a MIP model, to get a reduced model?

Does Highs provide postsolve? to transform a reduced solution of the reduced model to an original solution of the original model?

[jajhall]

Yes, use Highs::presolve(), Highs::getPresolvedLp(), Highs::postsolve(const HighsSolution& solution), then Highs::getSolution()

[linpeng0105]

Thank you, I have another question:

A MIP problem A.mps, after presolve reduction generates a reduced problem B.mps.
I solved B.mps and obtained a solution B.sol, with an objective function value of Value(B).
After the postsolve process, B.sol was used to obtain A.sol, with an objective function value of Value(A).

My question: Is Value(A) equal to Value(B)?

[jajhall]

Yes, they are equal, but the objective function of the presolved problem will generally have a nonzero constant offset