C Parameter Examples

The C interface defines a symbolic constant for each parameter. The symbolic constant name is prefixed by GRB_type_PAR_, where type is either INT, DBL, or STR. This is followed by the capitalized parameter name. For example, the symbolic constant for the integer Threads parameter (found in C header file gurobi_c.h) is:

#define GRB_INT_PAR_THREADS "Threads"

The routine you use to modify a parameter value depends on the type of the parameter. For a double-valued parameter, you would use GRBsetdblparam. Recall that models get their own environments once they are created, so you'll generally need to get the environment for a model before setting a parameter on that model.

To set the TimeLimit parameter for a model, you'd do:

  modelenv = GRBgetenv(model);
  error = GRBsetdblparam(modelenv, GRB_DBL_PAR_TIMELIMIT, 100.0);

If you'd prefer to use a string for the parameter name, you can also do:

  error = GRBsetdblparam(modelenv, "TimeLimit", 100.0);
The case of the string is ignored, as are underscores. Thus, TimeLimit and TIME_LIMIT are equivalent.

Use GRBgetdblparam to query the current value of a parameter:

  double currentvalue;
  error = GRBgetdblparam(modelenv, "TimeLimit", &currentvalue);

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.