Originally posted by: SystemAdmin

Hello! What I want to do is to subtract an IloNumExpr from a number. I want to put to an expression the following thing:
\{
for i
for j
for k
n-(n-k-1)*y[i][j]
\}
n is an integer and y is a decision variable

Cplex does not let me subtract a number in the addTerm method of the expression.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

You need to use the setConstant() member function to change the constant part of an expression.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

Thanks, Daniel. But then how will I subtract the expression from this constant part. I will say \{setConstant(n) \} and how will I say the \{ -(n-k+1)y[i][j] \}?
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

I suggest you take a good look at the IloCplexModeler class reference documentation. That is the superclass of IloCplex that provides the modeling API.
There you can find for example member function

IloNumExpr sum(double v, IloNumExpr e1);

that produces the sum of a constant and an expression.
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#DecisionOptimization