Originally posted by: MoodyAlam1

Hi, 

Could somebody confirm if there's a function in CPLEX Java library that I could use to get the natural log of a IloNumber? Something like "cplex.abs(var)" ? 

Cheers,

Moody Alam

There's no such thing as IloNumber, and (unlike the C++ API) the Java API does not have IloNum, so I'm guessing you mean IloNumVar? There's no built-in representation for the log of an IloNumVar because CPLEX solves linear and quadratic problems, and the natural log function would produce an expression neither linear nor quadratic. IloCplex.abs() is provided because it can internally linearize the resulting expression using an indicator constraint. Unfortunately, there's no way to linearize the log function.

Paul