有没有办法将 cplex 表达式 (docplex.mp.LinearExpr(...)) 提高到 python 中的 -1 或 3 次方？

Question

I have constructed a linear programming problem in Python and use the CPLEX solver. The variables are expressed as cplex expressions like docplex.mp.LinearExpr(...). The goal is to construct an objective where we optimize over a variable with an expression like that to the power -1 or 3:

Opt 1/variable

Unfortunately, I receive the following error message; docplex.mp.utils.DOcplexException: Cannot raise "docplex.mp.LinearExpr(...)" to the power -1. A variable's exponent must be 0, 1 or 2.

Does anyone know if there is a way to fix this problem? So is there a way to divide a certain number by a value equivalent to docplex.mp.LinearExpr(...)?

Answer 1

Erwin is correct as always. However in some limited cases you maybe able to rearrange your expressions to avoid dividing by a variable, eg change a <= 1 / var to a * var <= 1 . Without seeing more of your model we cannot know if this kind of simple rearrangement could work for you.

Answer 2

No, Cplex can only do linear and quadratic models. It is not a general-purpose nonlinear solver.

Note that: I have constructed a linear programming problem is not really true. This is now becoming a non-linear model.