Originally posted by: Perth2

I have a MIP model in CPLEX in which slack variables are naturally integer. This is because of the way the slack variables are defined in relation to other variables that are declared integer. In my implementation I have declared the slack variables continuous, that is I create them with the call  cplex.numVar(lowerBound, upperBound) in Java. Is there any reason to declare these naturally integer variables differently?

Is there any reason why you do not want to declare them integer?

CPLEX will detect that these variables are implied integer, so can omit that information. But unless there is a good reason to do that, I would not hide that information from CPLEX.