Documentation


GRBloadclientenv

int GRBloadclientenv ( GRBenv **envP,
    const char *logfilename,
    const char *computeserver,
    const char *router,
    const char *password,
    const char *group,
    int CStlsinsecure,
    int priority,
    double timeout )

Create a client environment on a compute server. Optimization models live within an environment, so this is typically the first Gurobi routine called in an application. This call specifies the compute server on which those optimization models will be solved, as well as the priority of the associated jobs.

This routine will also check the current working directory for a file named gurobi.env, and it will attempt to read parameter settings from this file if it exists. The file should be in PRM format (briefly, each line should contain a parameter name, followed by the desired value for that parameter).

In general, you should aim to create a single Gurobi environment in your program, even if you plan to work with multiple models. Reusing one environment is much more efficient than creating and destroying multiple environments. The one exception is if you are writing a multi-threaded program, since environments are not thread safe. In this case, you will need a separate environment for each of your threads.

Return value:

A non-zero return value indicates that there was a problem creating the environment. Refer to the Error Code table for a list of possible return values.

Arguments:

envP: The location in which the pointer to the newly created environment should be placed.

logfilename: The name of the log file for this environment. May be NULL (or an empty string), in which case no log file is created.

computeserver: A Compute Server. You can refer to the server using its name or its IP address. If you are using a non-default port, the server name should be followed by the port number (e.g., server1:61000)

router: The router for a Compute Server cluster. A router can be used to improve the robustness of a Compute Server deployment. You should refer to the router using either its name or its IP address. If no router is used (which is the typical case), pass an empty string.

password: The password for gaining access to the specified Compute Server cluster. Pass an empty string if no password is required.

group: The name of the Compute Server group.

CStlsinsecure: Indicates whether to use insecure mode in the TLS (Transport Layer Security). Set this to 0 unless your server administrator tells you otherwise.

priority: The priority of the job. Priorities must be between -100 and 100, with a default value of 0 (by convention). Higher priority jobs are chosen from the server job queue before lower priority jobs. Depending on the configuration of the server, a job with priority 100 runs immediately, bypassing the job queue and ignoring the job limit on the server. You should exercise caution with priority 100 jobs, since they can severely overload a server, which can cause jobs to fail, and in extreme cases can cause the server to crash. This behavior is managed by the HARDJOBLIMIT, and is disabled by default. Refer to the Gurobi Remote Services Reference Manual for more information on starting Compute Server options.

timeout: Queue timeout (in seconds). If the job doesn't reach the front of the queue before the specified timeout, the call will exit with a JOB_REJECTED error. Use -1 to indicate that the call should never timeout.

Example usage:

  GRBenv *env;
  error = GRBloadclientenv(&env, "gurobi.log",
                           "server1.mydomain.com,server2.mydomain.com",
                           "", "", "", 0, 5, -1.0);