Hi there,
I am wondering how I can use an if statement to turn a constraint on or off. For example in my problem I have the following constraint: subject to linctr14 {i in PeriodsCount: i == 1}: StorageEnergy[i] = (StorageStateCharge * StorageEnergyRating + ((StorageEfficiencyCharge * (StoragePowerCharge[i])) - ((StoragePowerDischarge[i]) / StorageEfficiencyDischarge))); Now, I only want to consider storage in my problem if an object storage actually exists. For that, I would have a StorageStatusFlag which if equal to "1" then I would consider the constraint in my problem. For example: If (StorageStatusFlag == 1) then subject to linctr14 {i in PeriodsCount: i == 1}: StorageEnergy[i] = (StorageStateCharge * StorageEnergyRating + ((StorageEfficiencyCharge * (StoragePowerCharge[i])) - ((StoragePowerDischarge[i]) / StorageEfficiencyDischarge))); end if This is what I used to do in "mosel" language from FICO Xpress (I don't have a license anymore so I am discovering GLPK ). How can I do this in GLPK language? What's the workaround that we can use for this? Many thanks in advance for your help. It's really appreciated. Kind regards, Manuel.