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

回答済み

dapei jiang

2021年05月17日 11:39 編集済み

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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

• 正式なコメント

  

  Simranjit Kaur

  • Gurobi Staff

  2025年06月23日 02:54 編集済み

  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

  2021年05月17日 12:14 編集済み

  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

  2021年05月17日 12:24

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

  Mr Najman, Thank you!

  0

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