I would like to write the following constraint, where $varBuyWater$ and $varSellWater$ are decision variables on how much water to buy and to sell. However, I do not want the solver to buy and sell water at the same time, because that makes no sense.
How do I force to solver to have either one of them, i.e. if $varBuyWater > 0$ then $varSellWater = 0$ and the other way around. Is there a way to do this>