Interrupt the optimization process of one of the optimization steps in a multi-objective MIP problem without stopping the hierarchical optimization process. Only available for multi-objective MIP models and when the where member variable is not equal to GRB.CB_MULTIOBJ (see the Callback Codes section for more information).

You would typically stop a multi-objective optimization step by querying the last finished number of multi-objectives steps, and using that number to stop the current step and move on to the next hierarchical objective (if any) as shown in the following example:

Example usage:

import gurobi.*;

public class Callback extends GRBCallback {
  private int objcnt;
  private long starttime;

  protected void callback() {
    try {
      if (where == GRB.CB_MULTIOBJ) {
        /* get current objective number */
        objcnt    = getIntInfo(GRB.CB_MULTIOBJ_OBJCNT);

        /* reset start time to current time */
        starttime = System.currentTimeMillis();

      } else if (System.currentTimeMillis() - starttime > BIG ||
                 /* takes too long or good enough */) {
        /* stop only this optimization step */

You should refer to the section on Multiple Objectives for information on how to specify multiple objective functions and control the trade-off between them.

void stopOneMultiObj ( int objcnt )


objnum: The number of the multi-objective optimization step to interrupt. For processes running locally, this argument can have the special value -1, meaning to stop the current step.