优化后评估pyscipopt Expr

Question

I have a question regarding PySCIPOpt: Is it possible to evaluate expressions (pyscipopt.scip.Expr) after optimization? Similar to calling getVal() for arguments of type pyscipopt.scip.Variable.

Answer 1

It is not (yet) possible to query the activity of a general constraint. This is only possible for linear and quadratic constraints, see http://scip-interfaces.github.io/PySCIPOpt/docs/html/classpyscipopt_1_1scip_1_1Model.html#a1e79bf20f168f7c55aa3fdf00491c898

You could turn your expression into an equation and check the value of the new slack variable:

c(x) >= b

turns into

c(x) - s == 0
s >= b