# ALESSANDRA VIEIRA

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## Activity overview

Latest activity by ALESSANDRA VIEIRA
• ALESSANDRA VIEIRA commented,

Hallo gurobot!  The question is :  GRBVar x;GRBLinExrpr b;GRBQuadExpr c;GRBLinExpr d;c=6*x;d=x+x;b= c+d; The solver does not accept, the sum of expr can be easily a LinExpr, but  I think is because...

• ALESSANDRA VIEIRA commented,

Hi Matthias, The problem is my array P_wind is one single function output, that was randomly chosen from one data  2-D array [T][N] that will be the Upper Bound (UB) for the Gurobi variable W_curt[...

• ALESSANDRA VIEIRA created a post,

### Bounds for Variable

I am using Gurobi 9.0, with C++. I am trying to put an array element, that is created for a C++ function ( use random) as a UPPER bound of a GRB Var array, as follows: for ( t = 0; t < z; t++) {  ...

• ALESSANDRA VIEIRA commented,

• ALESSANDRA VIEIRA created a post,

### Gurobi C++ expr sum

Hi Folks, I need some help with my code. I am using Gurobi C++. I did a QuadExpr sum += sum of GRBVar variables.  How is possible that this sum gives any value different than zero if my variables a...

• ALESSANDRA VIEIRA commented,

Hallo Jaromil, Yeah ... because if I join it then I get the error message about the list of arguments. "subproblem1 cb = subproblem1(P_wind,t_D_f,Pbss,Pbssd,Ecurrent); Severity    Code    Line    D...

• ALESSANDRA VIEIRA commented,

Hallo Jaromil,   I think we mismatch answers and questions please find above the piece of my callback.

• ALESSANDRA VIEIRA commented,

Hallo Jaromil,    Please find below the instantiation of part of the callback, that will be applied at the solution node. After I commented Ecurrent expression, then the optimization runs, without ...

• ALESSANDRA VIEIRA created a post,