Procedure GMP::Solver::InitializeEnvironment(solver, computeserver, password, priority, timeout, logfile)

GMP::Solver::InitializeEnvironment

The procedure GMP::Solver::InitializeEnvironment can be used to initialize a solver environment. By using the procedure GMP::Solver::FreeEnvironment you can free a solver environment; by using this procedure you can initialize it again.

Normally AIMMS initializes solver environments at startup and frees them when it is closed. The procedures GMP::Solver::InitializeEnvironment and GMP::Solver::FreeEnvironment can be used to initialize and free a solver environment multiple times inside one AIMMS sesstion. Both procedures are typically used for solvers running on a remote server or a cloud system.

Several environment parameters can be set using the optional arguments. Instead you can also use one of the following procedures to set these or other parameters:
GMP::Solver::InitializeEnvironment(
     solver,            ! (input) a solver
     [computeserver],   ! (input, optional) a string expression
     [password],        ! (input, optional) a string expression
     [priority],        ! (input, optional) integer, default 0
     [timeout],         ! (input, optional) integer, default -1
     [logfile]          ! (input, optional) a string expression
     )

Arguments

solver

An element in the set AllSolvers.

computeserver

A string containing a comma-separated list of compute servers. You can refer to compute server machines using their names or their IP addresses.

password

The password for gaining access to the specified compute servers. Do not specify this argument if no password is required.

priority

The priority of the job. Priorities must be between -100 and 100, with a default value of 0. Higher priority jobs are chosen from the server job queue before lower priority jobs.

timeout

Job queue timeout (in seconds). If the job does not reach the front of the queue before the specified timeout, the call will exit with an error. Use the default value of -1 to indicate that the call should never timeout.

logfile

The name of the log file for this environment. If this argument is not specified then no log file will be created for this environment.

Return Value

The procedure returns 1 on success, or 0 otherwise.

Note

  • If the solver environment is already initialized when this procedure is called, the solver environment will be freed first.

  • This procedure can be used in combination with a normal solve statement.

  • This procedure is only supported by Gurobi.

  • If the computeserver argument is not specified then the compute server must be specified via a Gurobi client license key file, or using the procedure GMP::Solver::SetEnvironmentStringParameter.

  • The computeserver argument can refer to a 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., myserver1:61000).

  • The computeserver argument may contain a comma-separated list of servers to increase robustness. If the first server in the list does not respond then the second will be tried, etc.

  • The optional arguments password, priority, timeout and logfile are only used if the optional argument computeserver is specified.

  • 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 procedure cannot be called inside a solver callback procedure.

  • This procedure cannot be called if one of the solver sessions is asynchronous executing.

Example

Assume that ‘MIPSolver’ is an element parameter with range AllSolvers and ‘myGMP’ is an element parameter with range AllGeneratedMathematicalPrograms.

MIPSolver := 'Gurobi 10.0';

! First solve using normal solve statement.

GMP::Solver::InitializeEnvironment( MIPSolver, computeserver: "myserver1:61000", priority: 10 );

solve MP1;

GMP::Solver::FreeEnvironment( MIPSolver );

! Second solve using GMP solve.

GMP::Solver::SetEnvironmentStringParameter( MIPSolver, "ComputeServer", "myserver1:61000" );
GMP::Solver::SetEnvironmentIntegerParameter( MIPSolver, "CSPriority", 10 );

GMP::Solver::InitializeEnvironment( MIPSolver );

mgGMP := GMP::Instance::Generate( MP2 );
GMP::Instance::Solve( myGMP );

GMP::Solver::FreeEnvironment( MIPSolver );

See also

The procedures GMP::Solver::FreeEnvironment, GMP::Solver::SetEnvironmentDoubleParameter, GMP::Solver::SetEnvironmentIntegerParameter and GMP::Solver::SetEnvironmentStringParameter.