Class MPICommunicator

Abort all processes associated with the communicator. For emergency use only.

Parameters:

• error_code (int) - error code passed back to the calling program (usually a shell) under most Unix implementations of MPI

Combine data from all processes and send result to all

Parameters:

• sendbuffer (Numeric.array) - an array holding the data that each process contributes
• receivebuffer (Numeric.array) - an array acting as a buffer for the result of the reduction
• operation (MPIOperationObject) - one of the operation objects: max, min, prod, sum, land, lor, lxor, band, bor, bxor, maxloc and minloc

Send data to all processes

Parameters:

• array (Numeric.array) - an array containing the data to be sent on the sending process and serving as a buffer for the incoming data on all processes. The shape and type of the array must be the same on all processes.
• root (int) - the rank of the sending process

Returns: MPICommunicator

a new communicator with the same properties as the original one

Check for incoming messages

Parameters:

• source (int or NoneType) - the rank of the process from which messages are accepted. None means data is accepted from any process.
• tag (int or NoneType) - Identifier that acts as a filter; only messages with a matching tag are considered. A value of None means that any tag will match.

Returns: NoneType or tuple

None if no messages are available, otherwise a tuple containing the source rank and the tag

Receive data from another process (non-blocking)

Parameters:

• data (Numeric.array) - a contiguous array object to which the incoming data is copied. It must have the right shape.
• source (int or NoneType) - the rank of the process from which data is accepted. None means data is accepted from any process.
• tag (int or NoneType) - Identifier that acts as a filter; only messages with a matching tag are received. A value of None means that any tag will match.

Returns: MPIRequest

MPI request object (used to wait for completion and obtain the received data)

Send data to another process (non-blocking)

Parameters:

• data (str or Numeric.array. Array arguments must have contiguous storage. General object arrays are not allowed.) - the data to be sent
• destination (int) - the rank of the destination process
• tag (int) - Identifier

Returns: MPIRequest

MPI request object (used to wait for completion)

Receive data from another process (blocking)

Parameters:

• data (Numeric.array or str) - either a contiguous array object, or a one-letter typecode (in practice, one would use Numeric.Int, Numeric.Float, etc.). If an array, the data is copied to the array, whic must have the right shape. If a typecode, an array of that type is created and used as the buffer for incoming data.
• source (int or NoneType) - the rank of the process from which data is accepted. None means data is accepted from any process.
• tag (int or NoneType) - Identifier that acts as a filter; only messages with a matching tag are received. A value of None means that any tag will match.

Returns: tuple

a tuple containing four elements: the array containing the data, the source process rank (an int), the message tag (an int), and the number of elements that were received (an int).

Receive string data from another process (blocking)

Parameters:

• source (int or NoneType) - the rank of the process from which data is accepted. None means data is accepted from any process.
• tag (int or NoneType) - Identifier that acts as a filter; only messages with a matching tag are received. A value of None means that any tag will match.

Returns: tuple

a tuple containing three elements: the string containing the data, the source process rank (an int), the message tag (an int).

Combine data from all processes and send result to one

Parameters:

• sendbuffer (Numeric.array) - an array holding the data that each process contributes
• receivebuffer (Numeric.array) - an array acting as a buffer for the result of the reduction. Used only by the process whose rank is root
• operation (MPIOperationObject) - one of the operation objects: max, min, prod, sum, land, lor, lxor, band, bor, bxor, maxloc and minloc
• root (int) - the rank of the process that received the result

Send data to another process (blocking)

Parameters:

• data (str or Numeric.array. Array arguments must have contiguous storage. General object arrays are not allowed.) - the data to be sent
• destination (int) - the rank of the destination process
• tag (int) - Identifier

Distribute data from each processpr to all other processesors

Parameters:

• send (Numeric.array) - an array of identical shape and type on all processes. It contains on each process the data that is sent.
• receive (Numeric.array) - an array whose type is the same as for the send array and which has an additional dimension (the first one) whose length is the number of processes. After the call, the value of receive[i] is equal to the contents of the array send in process i.

Create a communicator for a subset of the processes

The method should be called by all processes simultaneously. The return value will be the new communicator on those processes listed in ranks and None for the rest.

Parameters:

• ranks (list of int) - a list of ranks, one for each process that should belong to the new communicator

Returns:

a new communicator containing a subset of the processes participating in the original one