QSopt QSget_pi_array QSopt > Callable Library > Function List
  QSopt
  Downloads
  LP Info
  Software
  Problem Formats
  Callable Library
  Overview
>  Function List
  Rational Solver
  Beta
  Contact Info
Purpose
Copy the values of the dual variables into an array.
Synopsis
int QSget_pi_array (QSprob p, double *pi)
Arguments
p a handle to an initialized problem.
pi returns the values of the dual variables as an array; this should point to an array of length at least nrows, the number of rows in the problem.
Returns
A zero value if the function terminated correctly, and a non-zero value if an error occurred. Note that QSget_pi_array returns an error code if it is called with a specified problem that has not been solved with one of the optimization functions ( QSopt_dual or QSopt_primal) since the last time the problem was loaded or modified.
Description

This function returns the dual solution to the LP problem as a dense vector, that is, the values of all dual variables (both zero and non-zero) are returned in the array pi. Note that the values of the dual variables associated with lower and upper bounds are given implicitly by the array pi.

Example
/* p is an initialized QSprob, a handle to an existing LP problem  */

int rval, nrows;
double *pi;

nrows = QSget_rowcount (p);
pi = (double *) malloc (nrows * sizeof (double));

rval = QSget_pi_array (p, pi);
if (rval) {
    fprintf (stderr,
             "Could not get dual values, error code %d\n", rval);
} else {
    /* To print dual values with names, see QSget_solution() example. */
}

free (pi);
 
QSopt | Problem Formats | Downloads Back
Last Updated: November 2003