Originally posted by: Selectedbetter

Hello everyone,  we need some help about how to sum a const IloNumArray3, the question is:

At the first, we have "const IloIntVarArray3 x" in the void();

Let the x[i][j][k] represent the IloIntVarArray3 x. 

Then, we want to sum all k in a  given i and j, that is sum (x[i][j]), but we don't know how to do with.

We have tried like:

IloExpr expr(env);

for(k=0;k<n;++k)

 {
    expr+=x[i][j][k];                    
  }          

but we got an error says"IloExpr& IloNumExpr::operator+=const IloIntVar arg: mixing mismatch Environments" .

Wish all of you a happy new year!

Hi,

you wrote

IloExpr expr(env);

I wonder why you do not use the IloEnv you used previously for x

regards

Originally posted by: Selectedbetter

Dear AlexFleischer

Thank you for answering our question!

Under the void(); we have gotten the env like:

IloEnv env = cplex.getEnv();

so, when we need sum x[i][j], we just write 

IloExpr expr(env);

Do you mean the environment of x shoule be defined? But we think the environment have already declared in the void().

Actually, We want to know how to sum the x[i][j] up if we don't use the "expr".

What do you mean by 'in the void()'? Is this a function? Is this a callback's main() function?

Can you try this:

IloExpr expr(x.getEnv());
for (k = 0; k < n; k++)
   expr += x[i][j][k];

That should avoid the error about mixing environments.