get_primal_solution, get_ptr_primal_solution, get_var_primalresult

Returns the solution of the model.

unsigned char get_primal_solution(lprec *lp, REAL *pv);

unsigned char get_ptr_primal_solution(lprec *lp, REAL **ptr_pv);

REAL get_var_primalresult(lprec *lp, int index);

Return Value

get_primal_solution, get_ptr_primal_solution return TRUE (1) if the operation was successful. A return value of FALSE (0) indicates an error.
get_var_primalresult returns the value for index.

Parameters

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

An array that will contain the value of the objective function (element 0), values of the constraints (elements 1 till Nrows), and the values of the variables (elements Nrows+1 till Nrows+NColumns).

ptr_pv

The address of a pointer that will point to an array that will contain the value of the objective function (element 0), values of the constraints (elements 1 till Nrows), and the values of the variables (elements Nrows+1 till Nrows+NColumns).

index

index of the constraint/variable.

Remarks

The get_primal_solution, get_ptr_primal_solution, get_var_primalresult functions retrieve the values of the objective function, constraints and variables.
These values are only valid after a successful solve or lag_solve. Function get_primal_solution needs an array that is already dimensioned with 1 + get_Nrows + get_Ncolumns elements. get_ptr_primal_solution returns a pointer to an array already dimensioned by lp_solve. Element 0 is the value of the objective function, elements 1 till Nrows the values of the constraints and elements Nrows+1 till Nrows+NColumns the values of the variables. get_var_primalresult requires no array. index is the array element number of the above functions and returns the value for this array element.
Special considerations when presolve was done. When set_presolve is called before solve, then presolve can have deleted both rows and columns from the model because they could be eliminated. This influences get_primal_solution and get_ptr_primal_solution. These functions only report the values of the remaining variables and constraints. However get_var_primalresult returns all values, also the deleted ones by presolve. So index is the original index number as known by the caller.

Example

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

int main(void)
{
  lprec *lp;
  REAL pv[1+2+3], *ptr_pv;

  /* Create a new LP model */
  lp = make_lp(3, 2);
  if(lp == NULL) {
    fprintf(stderr, "Unable to create new LP model\n");
    return(1);
  }

  solve(lp);

  get_primal_solution(lp, pv);
  get_ptr_primal_solution(lp, &ptr_pv);

  delete_lp(lp);
  return(0);
}

lp_solve API reference