Environment

mpiexec()

A wrapper function for the MPI launcher executable. Returns a Cmd object pointing to the MPI launcher.

Usage

julia> run(`$(mpiexec()) -n 3 echo hello world`);
hello world
hello world
hello world

MPI.install_mpiexecjl(; command::String = "mpiexecjl",
                      destdir::String = joinpath(DEPOT_PATH[1], "bin"),
                      force::Bool = false, verbose::Bool = true)

Install the mpiexec wrapper to destdir directory, with filename command. Set force to true to overwrite an existing destination file with the same path. If verbose is true, the installation prints information about the progress of the process.

ThreadLevel

An Enum denoting the level of threading support in the current process:

• MPI.THREAD_SINGLE: Only one thread will execute.

• MPI.THREAD_FUNNELED: The process may be multi-threaded, but the application must ensure that only the main thread makes MPI calls. See Is_thread_main.

• MPI.THREAD_SERIALIZED: The process may be multi-threaded, and multiple threads may make MPI calls, but only one at a time (i.e. all MPI calls are serialized).

• MPI.THREAD_MULTIPLE: Multiple threads may call MPI, with no restrictions.

See also

• Init
• Query_thread

Abort(comm::Comm, errcode::Integer)

Make a “best attempt” to abort all tasks in the group of comm. This function does not require that the invoking environment take any action with the error code. However, a Unix or POSIX environment should handle this as a return errorcode from the main program.

External links

• MPI_Abort man page: OpenMPI, MPICH

Init(;threadlevel=:serialized, finalize_atexit=true, errors_return=true)

Initialize MPI in the current process. The keyword options:

• threadlevel: either :single, :funneled, :serialized (default), :multiple, or an instance of ThreadLevel.
• finalize_atexit: if true (default), adds an atexit hook to call MPI.Finalize if it hasn't already been called.
• errors_return: if true (default), will set the default error handlers for MPI.COMM_SELF and MPI.COMM_WORLD to be MPI.ERRORS_RETURN. MPI errors will then appear as Julia exceptions.

It will return the ThreadLevel value which MPI is initialized at.

All MPI programs must call this function at least once before calling any other MPI operations: the only MPI functions that may be called before MPI.Init are MPI.Initialized and MPI.Finalized.

It is safe to call MPI.Init multiple times, however it is not valid to call it after calling MPI.Finalize.

External links

• MPI_Init man page: OpenMPI, MPICH

• MPI_Init_thread man page: OpenMPI, MPICH

Query_thread()

Query the level of threading support in the current process. Returns a ThreadLevel value denoting

External links

• MPI_Query_thread man page: OpenMPI, MPICH

Is_thread_main()

Queries whether the current thread is the main thread according to MPI. This can be called by any thread, and is useful for the THREAD_FUNNELED ThreadLevel.

External links

• MPI_Is_thread_main man page: OpenMPI, MPICH

Initialized()

Returns true if MPI.Init has been called, false otherwise.

It is unaffected by MPI.Finalize, and is one of the few functions that may be called before MPI.Init.

External links

• MPI_Initialized man page: OpenMPI, MPICH

Finalize()

Marks MPI state for cleanup. This should be called after MPI.Init, and can be called at most once. No further MPI calls (other than Initialized or Finalized) should be made after it is called.

MPI.Init will automatically insert a hook to call this function when Julia exits, if it hasn't already been called.

External links

• MPI_Finalize man page: OpenMPI, MPICH

Finalized()

Returns true if MPI.Finalize has completed, false otherwise.

It is safe to call before MPI.Init and after MPI.Finalize.

External links

• MPI_Finalized man page: OpenMPI, MPICH

MPI.add_init_hook!(f)

Register a function f that will be called as f() when MPI.Init is called. These are invoked in a first-in, first-out (FIFO) order.

MPI.run_init_hooks()

Execute all functions that have been registered using MPI.add_init_hook!().

This function is executed automatically by MPI.Init() but must be invoked manually if MPI has been initialized externally by a direct call to MPI_Init(). It is safe to call this function multiple times (subsequent runs will be a no-op).

MPI.add_finalize_hook!(f)

Register a function f that will be called as f() when MPI.Finalizer is called. These are invoked in a last-in, first-out (LIFO) order.

MPIError

Error thrown when an MPI function returns an error code. The code field contains the MPI error code.

FeatureLevelError

Error thrown if a feature is not implemented in the current MPI backend.