get_mip_gap

Returns the MIP gap value.

REAL get_mip_gap(lprec *lp, unsigned char absolute);

Return Value

get_mip_gap returns the MIP gap value.

Parameters

lp

Pointer to previously created lp model. See return value of make_lp, read_lp, read_LP, read_mps, read_freemps, read_MPS, read_freeMPS, read_XLI

absolute

If TRUE then the absolute MIP gap is returned, else the relative MIP gap.

Remarks

The get_mip_gap function returns the MIP gap that specifies a tolerance for the branch and bound algorithm. This tolerance is the difference between the best-found solution yet and the current solution. If the difference is smaller than this tolerance then the solution (and all the sub-solutions) is rejected. This can result in faster solving times, but results in a solution which is not the perfect solution. So be careful with this tolerance.
The default mip_gap value is 1e-9

Example

#include <stdio.h>
#include <stdlib.h>
#include "lp_lib.h"

int main(void)
{
  lprec *lp;
  REAL mip_gap;

  /* Create a new LP model */
  lp = make_lp(0, 0);
  if(lp == NULL) {
    fprintf(stderr, "Unable to create new LP model\n");
    return(1);
  }

  mip_gap = get_mip_gap(lp, TRUE); /* Will return 1e-9 */

  delete_lp(lp);
  return(0);
}

lp_solve API reference

See Also make_lp, read_lp, read_LP, read_mps, read_freemps, read_MPS, read_freeMPS, read_XLI, set_mip_gap, get_epsd, set_epsd, set_infinite, get_infinite, set_epsint, get_epsint, set_epsb, get_epsb, set_epsel, get_epsel, get_epspivot, set_epspivot, set_epsperturb, get_epsperturb