Originally posted by: Amani_Jerbi

Please how to write a mathematical expression or formula in OPL. I need to calculate the cost then use it in the objective function.

Do I write it in execute block ? 

Thanks.

Hi,

you do not need any execute block for that. Let me give you a small example:

dvar float+ Gas;
dvar float+ Chloride;

dexpr float objective=40 * Gas + 50 * Chloride;
maximize objective;
 
subject to {
  ctMaxTotal:     
    Gas + Chloride <= 50;
  ctMaxTotal2:    
    3 * Gas + 4 * Chloride <= 180;
  ctMaxChloride:  
    Chloride <= 40;
}

regards

Originally posted by: Amani_Jerbi

Thank you so much.