Originally posted by: SystemAdmin

[pmarley2 said:]

Hi all,

I am trying to write a conditional statement into my constraints. However, when I use decision variables inside the condition, I get an error. For example,

1 subject to {
2    forall (t in 0..nbHours-1) {
3        forall (p in providers) {
4                if (Power[p][t]/(suppliers[p][4] - suppliers[p][3]) >= 1)
5                {
6                        abs(Power[p][t] - Power[p][t+1]) <= suppliers[p][5];<br />7                }
8        }
9    } }

I get an error on line 4 that says "Decision variable "Power" not allowed."

I try to bypass using the if statement by writing the following.

1 subject to {
2    forall (t in 0..nbHours-1) {
3        forall (p in providers) {
4                (Power[p][t]/(suppliers[p][4] - suppliers[p][3]) >= 1) &&
5                abs(Power[p][t] - Power[p][t+1]) <= suppliers[p][5];<br />6        }
7    } }

And the code works correctly. But is there a way to write a conditional statement in an easier way?

Thanks.
#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

[afleischer said:]

Hi,

it is not allowed to use if with decision variables (if cannot be part of a constraint)
but what you can do is use the => logical

so you can rewrite

if (Power[p][t]/(suppliers[p][4] - suppliers[p][3]) >= 1)
                {
                      abs(Power[p][t] - Power[p][t+1]) <= suppliers[p][5];<br />              }

into


(Power[p][t]/(suppliers[p][4] - suppliers[p][3]) >= 1) => (abs(Power[p][t] - Power[p][t+1]) <= suppliers[p][5])<br />
Alex

#DecisionOptimization
#OPLusingCPLEXOptimizer