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XPRSsetcbintsol

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Purpose

Declares a user integer solution callback function, called every time an integer solution is found by heuristics or during the Branch and Bound search.

Synopsis

int XPRS_CC XPRSsetcbintsol(XPRSprob prob, void (XPRS_CC *fuis)(XPRSprob my_prob, void *my_object), void *object);

Arguments

prob	The current problem.
fuis	The callback function which takes two arguments, my_prob and my_object, and has no return value. This function is called if the current node is found to have an integer feasible solution, i.e. every time an integer feasible solution is found.
my_prob	The problem passed to the callback function, fuis.
my_object	The user-defined object passed as object when setting up the callback with XPRSsetcbintsol.
object	A user-defined object to be passed to the callback function, fuis.

Example

The following example prints integer solutions as they are discovered in the global search, without using the solution file:

XPRSsetcbintsol(prob,printsol,NULL);
XPRSmaxim(prob,"g");

The callback function might resemble:

void XPRS_CC printsol(XPRSprob my_prob, void *my_object)
{
  int i, cols, *x;
  double objval;

  XPRSgetintattrib(my_prob, XPRS_COLS, &cols);
  XPRSgetdblattrib(my_prob, XPRS_LPOBJVAL, &objval);
  x = malloc(cols * sizeof(int));
  XPRSgetlpsol(my_prob, x, NULL, NULL, NULL);

  printf("\nInteger solution found: %f\n", objval);
  for(i=0;i<cols;i++) printf(" x[%d] = %d\n", i, x[i]);
}

Further information

This callback is useful if the user wants to retrieve the integer solution when it is found.

Related topics

XPRSsetcbchgnode, XPRSsetcboptnode, XPRSsetcbinfnode, XPRSsetcbnodecutoff, XPRSsetcbchgbranch, XPRSsetcbprenode.

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