# set_rh_range Set the range on a constraint. unsigned char set_rh_range(lprec *lp, int row, REAL deltavalue); Return Value set_rh_range returns TRUE (1) if the operation was successful. A return value of FALSE (0) indicates an error. Parameters lp 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 row The row number of the constraint on which the range must be set. It must be between 1 and the number of rows in the lp. deltavalue The range on the constraint. Remarks The set_rh_range function sets a range on the constraint (row) identified by row. Setting a range on a row is the way to go instead of adding an extra constraint (row) to the model. Setting a range doesn't increase the model size that means that the model stays smaller and will be solved faster. If the row has a less than constraint then the range means setting a minimum on the constraint that is equal to the RHS value minus the range. If the row has a greater than constraint then the range means setting a maximum on the constraint that is equal to the RHS value plus the range. Note that the range value is the difference value and not the absolute value. Example
    #include <stdio.h>
    #include <stdlib.h>
    #include "lp_lib.h"

    int main(void)
    {
      lprec *lp;

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

      set_rh_range(lp, 1, 1.0);

      delete_lp(lp);
      return(0);
    }
lp_solve API reference See Also make_lp, copy_lp, read_lp, read_LP, read_mps, read_freemps, read_MPS, read_freeMPS, read_XLI, get_rh_range