how do I change variable type with c++ API?

Answered

dapei jiang

• May 17, 2021 11:39
• Edited

Hi, everyone, I'm practice with the diet_c++.cpp, I want to change the variable type, I modified the API like below, but the results show it doesn't work, could anyone tell me what mistake I was take?

Thanks.

 

// Create decision variables for the nutrition information,
// which we limit via bounds
nutrition = model.addVars(minNutrition, maxNutrition, nullptr, 0, Categories, nCategories);
//nutrition->set(GRB_CharAttr_VType, GRB_INTEGER); //修改变量类型为整型变量
for (size_t p = 0; p < nCategories; ++p)
{
nutrition[p].set(GRB_CharAttr_VType, GRB_INTEGER);
}

// Create decision variables for the foods to buy
buy = model.addVars(nullptr, nullptr, cost, 0, Foods, nFoods);
//buy->set(GRB_CharAttr_VType, GRB_INTEGER);
for (size_t p = 0; p < nCategories; ++p)
{
buy[p].set(GRB_CharAttr_VType, GRB_INTEGER);
}

 

0

• Official comment

  

  Simranjit Kaur

  Gurobi Staff

  • December 06, 2024 00:31

  This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.
• 

  Jaromił Najman

  Gurobi Staff

  • May 17, 2021 12:14
  • Edited

  Hi Dapei,

  Except for

  for (size_t p = 0; p < nCategories; ++p)
  {
    buy[p].set(GRB_CharAttr_VType, GRB_INTEGER);
  }

  which should read

  for(size_t p = 0; p < nFoods /* there are only nFoods "buy" variables */; ++p)
  {
    buy[p].set(GRB_CharAttr_VType, GRB_INTEGER);
  }

  the code looks fine. Why do you think that it does not work?

  Best regards,
  Jaromił

  0
• 

  dapei jiang

  • May 17, 2021 12:24

  

  

  

  oooooooooh! I make a foolish mistake, I'm so stupid. 

  Mr Najman, Thank you!

  0

Post is closed for comments.