Try our new documentation site (beta).


/* Copyright 2016, Gurobi Optimization, Inc. */

/* This example reads a model from a file and tunes it.
   It then writes the best parameter settings to a file
   and solves the model using these parameters. */

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "gurobi_c.h"

main(int   argc,
     char *argv[])
  GRBenv   *env   = NULL;
  GRBmodel *model = NULL;
  int       tuneresultcount;
  int       error = 0;

  if (argc < 2) {
    fprintf(stderr, "Usage: tune_c filename\n");

  /* Create environment */

  error = GRBloadenv(&env, "tune_c.log");
  if (error) goto QUIT;

  /* Read model from file */

  error = GRBreadmodel(env, argv[1], &model);
  if (error) goto QUIT;

  /* Set the TuneResults parameter to 1 */

  error = GRBsetintparam(GRBgetenv(model), GRB_INT_PAR_TUNERESULTS, 1);
  if (error) goto QUIT;

  /* Tune the model */

  error = GRBtunemodel(model);
  if (error) goto QUIT;

  /* Get the number of tuning results */

  error = GRBgetintattr(model, GRB_INT_ATTR_TUNE_RESULTCOUNT, &tuneresultcount);
  if (error) goto QUIT;

  if (tuneresultcount > 0) {

    /* Load the best tuned parameters into the model's environment */

    error = GRBgettuneresult(model, 0);
    if (error) goto QUIT;

    /* Write tuned parameters to a file */

    error = GRBwrite(model, "tune.prm");
    if (error) goto QUIT;

    /* Solve the model using the tuned parameters */

    error = GRBoptimize(model);
    if (error) goto QUIT;


  /* Error reporting */

  if (error) {
    printf("ERROR: %s\n", GRBgeterrormsg(env));

  /* Free model */


  /* Free environment */


  return 0;

Try Gurobi for Free

Choose the evaluation license that fits you best, and start working with our Expert Team for technical guidance and support.

Evaluation License
Get a free, full-featured license of the Gurobi Optimizer to experience the performance, support, benchmarking and tuning services we provide as part of our product offering.
Academic License
Gurobi supports the teaching and use of optimization within academic institutions. We offer free, full-featured copies of Gurobi for use in class, and for research.
Cloud Trial

Request free trial hours, so you can see how quickly and easily a model can be solved on the cloud.