set_floor_first

Specifies which branch to take first in branch-and-bound algorithm.

void set_floor_first(lprec *lp, short floor_first);

Return Value

set_floor_first has no return value.

Parameters

Pointer to previously created lp model. See return value of make_lp, copy_lp, read_lp, read_lp_file, read_LP, read_mps, read_MPS

floor_first

Specifies which branch to take first in branch-and-bound algorithm. Can by any of the following values:

BRANCH_CEILING (0)	Take ceiling branch first
BRANCH_FLOOR (1)	Take floor branch first
BRANCH_AUTOMATIC (2)	Algorithm decides which branch being taken first

Remarks

The set_floor_first function specifies which branch to take first in branch-and-bound algorithm. This can influence solving times considerably. Depending on the model one rule can be best and for another model another rule.
The default is BRANCH_FLOOR (1).

Example

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

int main(void)
{
  lprec *lp;

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

  set_floor_first(lp, BRANCH_AUTOMATIC);

  delete_lp(lp);
  return(0);
}

lp_solve API reference