Configuration

Solver configuration parameters: solverCfg.jl

In order to load currently defined solver parameters, the following file may be included in the script, which defines the solParams array:

include("$(Pkg.dir("COBRA"))/config/solverCfg.jl")

Then, the COBRA solver can be set with:

solver = changeCobraSolver(solverName, solParams);

If specific solver parameters should be set, the file solverCfg.jl may also be edited, or a new file mySolverCfg.jl can be created in the folder config loaded as:

include("config/mySolverCfg.jl")

The solver can then be set in a similar way with the additional argument solParams in changeCobraSolver.

In general, an array with all solver parameters is defined as follows:

solParams = [(:parameter, value)]

For the CPLEX solver, a list of all CPLEX parameters can be found here. The array of solver parameters can be defined as follows:

solParams = [
    # decides whether or not results are displayed on screen in an application of the C API.
    (:CPX_PARAM_SCRIND,         0);

    # sets the parallel optimization mode. Possible modes are automatic, deterministic, and opportunistic.
    (:CPX_PARAM_PARALLELMODE,   1);

    # sets the default maximal number of parallel threads that will be invoked by any CPLEX parallel optimizer.
    (:CPX_PARAM_THREADS,        1);

    # partitions the number of threads for CPLEX to use for auxiliary tasks while it solves the root node of a problem.
    (:CPX_PARAM_AUXROOTTHREADS, 2);

    # decides how to scale the problem matrix.
    (:CPX_PARAM_SCAIND,         1);

    # controls which algorithm CPLEX uses to solve continuous models (LPs).
    (:CPX_PARAM_LPMETHOD,       0)
] #end of solParams

SSH connection details: sshCfg.jl

A parallel pool with workers on SSH nodes can be created using:

include("$(Pkg.dir("COBRA"))/src/connect.jl")
workersPool, nWorkers = createPool(12, true, "mySSHCfg.jl")

which will connect 12 local workers, and all workers defined in mySSHCfg.jl. An example connection file is provided in the config/ folder of the COBRA package installation folder.

An array with all connection details to SSH nodes is defined as follows:

sshWorkers = Array{Dict{Any, Any}}(1)

sshWorkers[1,:] = Dict( "usernode"   => "first.last@server.com",
                        "procs"  => 32,
                        "dir"    => `~/COBRA.jl/`,
                        "flags"  => `-4 -p22`,
                        "exename"=> "/usr/bin/julia/bin/./julia")

Make sure that the size of sshWorkers is properly set.