Adding all violated cuts at the root node

回答済み

THI THANH TU LE

2026年01月22日 12:16

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Hi,
I am truggeling with adding all violated cuts at the root node.
I want at the root node: Gurobi added violated cuts → reoptimize → add new violated cuts → reoptimize → …→ no violated cuts are found.
However, Gurobi jumped to the other nodes before adding all violated cuts at the root node.
Is there any way to add all cuts that I want to add at the root node?

My C++ code is as follows:
void callback() override {
  try {
     if (where == GRB_CB_MIPNODE) {
        int status = getIntInfo(GRB_CB_MIPNODE_STATUS);
        if (status != GRB_OPTIMAL)
           return;
        double nodecnt = getDoubleInfo(GRB_CB_MIPNODE_NODCNT);
        std::vector<double> xvals(num_vars);
        std::vector<std::vector<double>> zvals(
           num_vars, std::vector<double>(num_vars, 0.0));

        for (size_t i = 0; i < num_vars; ++i)
           xvals[i] = getNodeRel(x[i]);

        for (auto& it : z) {
           auto [i, j] = it.first;
           double val = getNodeRel(it.second);
           zvals[i][j] = val;
           zvals[j][i] = val;
        }

        std::vector<Cut> cuts;
        if (nodecnt == 0) {  
           cuts.clear();
           separateCutsfor2Variables(x, z, xvals, zvals, num_vars, tolerance, num_vars, cuts);
           for (auto& c : cuts) {
              addCut(c.expr <= c.rhs);
           }
           cuts.clear();
           separateViolatedCutsfor3Variables(x, z, xvals, zvals, num_vars, tolerance, 3 * num_vars, cuts);
           for (auto& c : cuts) {
              addCut(c.expr <= c.rhs);
           }
           return;
        }

Could you please help me to solve the issue?
Thank you very much!

関連

• Callbacks
• Lazy Constraints

0

• 

  Riley Clement

  • Gurobi Staff

  2026年01月31日 00:35

  Hi Thi,

  I don't think you will be able to have the level of control you are wanting, but you can try to postpone the branching as long as possible by increasing the value of the CutPasses parameter.

  - Riley

  0

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