put_bb_nodefunc

Allows to set a user function that specifies which non-integer variable to select next to make integer in the B&B solve.

void put_bb_nodefunc(lprec *lp, lphandleint_intfunc newnode, void *bbnodehandle);

Return Value

put_bb_nodefunc has no return value.

Parameters

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

newnode

The node selection routine.

typedef int (__WINAPI lphandleint_intfunc)(lprec *lp, void *bb_nodehandle, int vartype);

The routine must return the node (column number) to make integer. vartype is at this moment always equal to BB_INT (1).
When 0 is returned then it indicates that all variables are integer.
When a negative value is returned, lp_solve will determine the next variable to make integer as if the routine is not set.
Note the __WINAPI attribute. This is important under Windows. It ensures __stdcall calling convention which is required.

bb_nodehandle

A parameter that will be provided to the node selection routine.

Remarks

Allows to set a user function that specifies which non-integer variable to select next to make integer in the B&B solve. Via this routine the user can implement his own rule to select the next non-integer variable to make integer. This overrules the setting of set_bb_rule.

Example

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

int __WINAPI nodefunction(lprec *lp, void *bb_nodehandle, int vartype)
{
 int node = -1;

 /* determine node to make integer */

 return(node);
}

int main(void)
{
  lprec *lp;

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

  put_bb_nodefunc(lp, nodefunction, NULL);

  solve(lp);

  delete_lp(lp);
  return(0);
}

lp_solve API reference