Hello, I am very new to OPL. After solving the original model, I want to change the coefficient of indexed decision variable, and change RHS of one of the constraints, and the solve model with new parameters. However, I am not able to do so. Primary challenge I am facing is that my decision variables and constraints are indexed. Any help is much appreciated. Thanks.

```
// .dat file
Products = { "chair", "table" };
Rescources = { "mahogany", "labor" };
Price = [45, 80];
Rescource_capacity = [400, 450];
Product_rescources = [[5, 20], [10, 15]];
// .mod file
{string} Products = ...;
int Price[Products] = ...;
{string} Rescources = ...;
int Rescource_capacity[Rescources] = ...;
int Product_rescources[Rescources][Products] = ...;
dvar float+ Produce[Products];
maximize
sum( p in Products )
Produce[p] * Price[p];
subject to {
forall( r in Rescources)
ctCapacity:
sum( p in Products )
Product_rescources[r][p] * Produce[p] <= Rescource_capacity[r];
}
// Solution
tuple ProduceSolutionT{
string Products;
float value;
};
{ProduceSolutionT} ProduceSolution = {<p, Produce[p]> | p in Products};
execute{
writeln(" Maximum profit = " , cplex.getObjValue());
writeln(ProduceSolution);
// writeln(Produce["table"]);
}
// Above code works absolutely fine and returns
// solution (optimal) with objective 2200
// Maximum profit = 2200
// {<"chair" 24> <"table" 14>}
// **********************BELOW IS MY QUESTION**************************
// Now I want to update the objective coefficient of lets say the first product
// 'chair', and say, i want to update the RHS of the first constraint. How to do this
// i know cplex.setObjCoef(thisOplModel.chair, 60) will work, if i have defined chair
// as a decision variable, but i have indexed it as Produce["chair"] ..
// after updations, i again i want to solve the model.
// I tried something on below lines, but doesn't work
main {
cplex.setObjCoef(thisOplModel.Produce["chair"], 80);
// at present RHS of first constraint = 400,
// how to change it to 500 (say). I am not sure how to pick the
// first constraint (there are 2 in total)
cplex.solve();
thisOplModel.postProcess();
}
```

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Bhartendu Awasthi

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