mpi4py.MPI.Comm

class mpi4py.MPI.Comm

Bases: object

Communication context.

static __new__(cls, comm=None)

Parameters:

comm (Comm | None)

Return type:

Self

Methods Summary

Abort([errorcode])	Terminate the MPI execution environment.
Ack_failed([num_to_ack])	Acknowledge failures on a communicator.
Agree(flag)	Blocking agreement.
Allgather(sendbuf, recvbuf)	Gather to All.
Allgather_init(sendbuf, recvbuf[, info])	Persistent Gather to All.
Allgatherv(sendbuf, recvbuf)	Gather to All Vector.
Allgatherv_init(sendbuf, recvbuf[, info])	Persistent Gather to All Vector.
Allreduce(sendbuf, recvbuf[, op])	Reduce to All.
Allreduce_init(sendbuf, recvbuf[, op, info])	Persistent Reduce to All.
Alltoall(sendbuf, recvbuf)	All to All Scatter/Gather.
Alltoall_init(sendbuf, recvbuf[, info])	Persistent All to All Scatter/Gather.
Alltoallv(sendbuf, recvbuf)	All to All Scatter/Gather Vector.
Alltoallv_init(sendbuf, recvbuf[, info])	Persistent All to All Scatter/Gather Vector.
Alltoallw(sendbuf, recvbuf)	All to All Scatter/Gather General.
Alltoallw_init(sendbuf, recvbuf[, info])	Persistent All to All Scatter/Gather General.
Attach_buffer(buf)	Attach a user-provided buffer for sending in buffered mode.
Barrier()	Barrier synchronization.
Barrier_init([info])	Persistent Barrier.
Bcast(buf[, root])	Broadcast data from one process to all other processes.
Bcast_init(buf[, root, info])	Persistent Broadcast.
Bsend(buf, dest[, tag])	Blocking send in buffered mode.
Bsend_init(buf, dest[, tag])	Persistent request for a send in buffered mode.
Call_errhandler(errorcode)	Call the error handler installed on a communicator.
Clone()	Clone an existing communicator.
Compare(comm)	Compare two communicators.
Create(group)	Create communicator from group.
Create_errhandler(errhandler_fn)	Create a new error handler for communicators.
Create_keyval([copy_fn, delete_fn, nopython])	Create a new attribute key for communicators.
Delete_attr(keyval)	Delete attribute value associated with a key.
Detach_buffer()	Remove an existing attached buffer.
Disconnect()	Disconnect from a communicator.
Dup([info])	Duplicate a communicator.
Dup_with_info(info)	Duplicate a communicator with hints.
Flush_buffer()	Block until all buffered messages have been transmitted.
Free()	Free a communicator.
Free_keyval(keyval)	Free an attribute key for communicators.
Gather(sendbuf, recvbuf[, root])	Gather data to one process from all other processes.
Gather_init(sendbuf, recvbuf[, root, info])	Persistent Gather.
Gatherv(sendbuf, recvbuf[, root])	Gather Vector.
Gatherv_init(sendbuf, recvbuf[, root, info])	Persistent Gather Vector.
Get_attr(keyval)	Retrieve attribute value by key.
Get_errhandler()	Get the error handler for a communicator.
Get_failed()	Extract the group of failed processes.
Get_group()	Access the group associated with a communicator.
Get_info()	Return the current hints for a communicator.
Get_name()	Get the print name for this communicator.
Get_parent()	Return the parent intercommunicator for this process.
Get_rank()	Return the rank of this process in a communicator.
Get_size()	Return the number of processes in a communicator.
Get_topology()	Return the type of topology (if any) associated with a communicator.
Iagree(flag)	Nonblocking agreement.
Iallgather(sendbuf, recvbuf)	Nonblocking Gather to All.
Iallgatherv(sendbuf, recvbuf)	Nonblocking Gather to All Vector.
Iallreduce(sendbuf, recvbuf[, op])	Nonblocking Reduce to All.
Ialltoall(sendbuf, recvbuf)	Nonblocking All to All Scatter/Gather.
Ialltoallv(sendbuf, recvbuf)	Nonblocking All to All Scatter/Gather Vector.
Ialltoallw(sendbuf, recvbuf)	Nonblocking All to All Scatter/Gather General.
Ibarrier()	Nonblocking Barrier.
Ibcast(buf[, root])	Nonblocking Broadcast.
Ibsend(buf, dest[, tag])	Nonblocking send in buffered mode.
Idup([info])	Nonblocking duplicate a communicator.
Idup_with_info(info)	Nonblocking duplicate a communicator with hints.
Iflush_buffer()	Nonblocking flush for buffered messages.
Igather(sendbuf, recvbuf[, root])	Nonblocking Gather.
Igatherv(sendbuf, recvbuf[, root])	Nonblocking Gather Vector.
Improbe([source, tag, status])	Nonblocking test for a matched message.
Iprobe([source, tag, status])	Nonblocking test for a message.
Irecv(buf[, source, tag])	Nonblocking receive.
Ireduce(sendbuf, recvbuf[, op, root])	Nonblocking Reduce to Root.
Ireduce_scatter(sendbuf, recvbuf[, ...])	Nonblocking Reduce-Scatter (vector version).
Ireduce_scatter_block(sendbuf, recvbuf[, op])	Nonblocking Reduce-Scatter Block (regular, non-vector version).
Irsend(buf, dest[, tag])	Nonblocking send in ready mode.
Is_inter()	Return whether the communicator is an intercommunicator.
Is_intra()	Return whether the communicator is an intracommunicator.
Is_revoked()	Indicate whether the communicator has been revoked.
Iscatter(sendbuf, recvbuf[, root])	Nonblocking Scatter.
Iscatterv(sendbuf, recvbuf[, root])	Nonblocking Scatter Vector.
Isend(buf, dest[, tag])	Nonblocking send.
Isendrecv(sendbuf, dest[, sendtag, recvbuf, ...])	Nonblocking send and receive.
Isendrecv_replace(buf, dest[, sendtag, ...])	Send and receive a message.
Ishrink()	Nonblocking shrink a communicator to remove all failed processes.
Issend(buf, dest[, tag])	Nonblocking send in synchronous mode.
Join(fd)	Interconnect two processes connected by a socket.
Mprobe([source, tag, status])	Blocking test for a matched message.
Precv_init(buf, partitions[, source, tag, info])	Create request for a partitioned recv operation.
Probe([source, tag, status])	Blocking test for a message.
Psend_init(buf, partitions, dest[, tag, info])	Create request for a partitioned send operation.
Recv(buf[, source, tag, status])	Blocking receive.
Recv_init(buf[, source, tag])	Create a persistent request for a receive.
Reduce(sendbuf, recvbuf[, op, root])	Reduce to Root.
Reduce_init(sendbuf, recvbuf[, op, root, info])	Persistent Reduce to Root.
Reduce_scatter(sendbuf, recvbuf[, ...])	Reduce-Scatter (vector version).
Reduce_scatter_block(sendbuf, recvbuf[, op])	Reduce-Scatter Block (regular, non-vector version).
Reduce_scatter_block_init(sendbuf, recvbuf)	Persistent Reduce-Scatter Block (regular, non-vector version).
Reduce_scatter_init(sendbuf, recvbuf[, ...])	Persistent Reduce-Scatter (vector version).
Revoke()	Revoke a communicator.
Rsend(buf, dest[, tag])	Blocking send in ready mode.
Rsend_init(buf, dest[, tag])	Persistent request for a send in ready mode.
Scatter(sendbuf, recvbuf[, root])	Scatter data from one process to all other processes.
Scatter_init(sendbuf, recvbuf[, root, info])	Persistent Scatter.
Scatterv(sendbuf, recvbuf[, root])	Scatter Vector.
Scatterv_init(sendbuf, recvbuf[, root, info])	Persistent Scatter Vector.
Send(buf, dest[, tag])	Blocking send.
Send_init(buf, dest[, tag])	Create a persistent request for a standard send.
Sendrecv(sendbuf, dest[, sendtag, recvbuf, ...])	Send and receive a message.
Sendrecv_replace(buf, dest[, sendtag, ...])	Send and receive a message.
Set_attr(keyval, attrval)	Store attribute value associated with a key.
Set_errhandler(errhandler)	Set the error handler for a communicator.
Set_info(info)	Set new values for the hints associated with a communicator.
Set_name(name)	Set the print name for this communicator.
Shrink()	Shrink a communicator to remove all failed processes.
Split([color, key])	Split communicator by color and key.
Split_type(split_type[, key, info])	Split communicator by split type.
Ssend(buf, dest[, tag])	Blocking send in synchronous mode.
Ssend_init(buf, dest[, tag])	Persistent request for a send in synchronous mode.
allgather(sendobj)	Gather to All.
allreduce(sendobj[, op])	Reduce to All.
alltoall(sendobj)	All to All Scatter/Gather.
barrier()	Barrier synchronization.
bcast(obj[, root])	Broadcast.
bsend(obj, dest[, tag])	Send in buffered mode.
f2py(arg)
free()	Call Free if not null or predefined.
fromhandle(handle)	Create object from MPI handle.
gather(sendobj[, root])	Gather.
ibsend(obj, dest[, tag])	Nonblocking send in buffered mode.
improbe([source, tag, status])	Nonblocking test for a matched message.
iprobe([source, tag, status])	Nonblocking test for a message.
irecv([buf, source, tag])	Nonblocking receive.
isend(obj, dest[, tag])	Nonblocking send.
issend(obj, dest[, tag])	Nonblocking send in synchronous mode.
mprobe([source, tag, status])	Blocking test for a matched message.
probe([source, tag, status])	Blocking test for a message.
py2f()
recv([buf, source, tag, status])	Receive.
reduce(sendobj[, op, root])	Reduce to Root.
scatter(sendobj[, root])	Scatter.
send(obj, dest[, tag])	Send in standard mode.
sendrecv(sendobj, dest[, sendtag, recvbuf, ...])	Send and Receive.
ssend(obj, dest[, tag])	Send in synchronous mode.

Attributes Summary

group	Group.
handle	MPI handle.
info	Info hints.
is_inter	Is intercommunicator.
is_intra	Is intracommunicator.
is_topo	Is a topology.
name	Print name.
rank	Rank of this process.
size	Number of processes.
topology	Topology type.

Methods Documentation

Abort(errorcode=0)

Terminate the MPI execution environment.

Warning

The invocation of this method prevents the execution of various Python exit and cleanup mechanisms. Use this method as a last resort to prevent parallel deadlocks in case of unrecoverable errors.

Parameters:

errorcode (int)

Return type:

NoReturn

Ack_failed(num_to_ack=None)

Acknowledge failures on a communicator.

Parameters:

num_to_ack (int | None)

Return type:

int

Agree(flag)

Blocking agreement.

Parameters:

flag (int)

Return type:

int

Allgather(sendbuf, recvbuf)

Gather to All.

Gather data from all processes and broadcast the combined data to all other processes.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecB)

Return type:

None

Allgather_init(sendbuf, recvbuf, info=INFO_NULL)

Persistent Gather to All.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecB)

• info (Info)

Return type:

Prequest

Allgatherv(sendbuf, recvbuf)

Gather to All Vector.

Gather data from all processes and send it to all other processes providing different amounts of data and displacements.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecV)

Return type:

None

Allgatherv_init(sendbuf, recvbuf, info=INFO_NULL)

Persistent Gather to All Vector.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecV)

• info (Info)

Return type:

Prequest

Allreduce(sendbuf, recvbuf, op=SUM)

Reduce to All.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec)

• op (Op)

Return type:

None

Allreduce_init(sendbuf, recvbuf, op=SUM, info=INFO_NULL)

Persistent Reduce to All.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec)

• op (Op)

• info (Info)

Return type:

Prequest

Alltoall(sendbuf, recvbuf)

All to All Scatter/Gather.

Send data to all processes and recv data from all processes.

Parameters:

• sendbuf (BufSpecB | InPlace)

• recvbuf (BufSpecB)

Return type:

None

Alltoall_init(sendbuf, recvbuf, info=INFO_NULL)

Persistent All to All Scatter/Gather.

Parameters:

• sendbuf (BufSpecB | InPlace)

• recvbuf (BufSpecB)

• info (Info)

Return type:

Prequest

Alltoallv(sendbuf, recvbuf)

All to All Scatter/Gather Vector.

Send data to all processes and recv data from all processes providing different amounts of data and displacements.

Parameters:

• sendbuf (BufSpecV | InPlace)

• recvbuf (BufSpecV)

Return type:

None

Alltoallv_init(sendbuf, recvbuf, info=INFO_NULL)

Persistent All to All Scatter/Gather Vector.

Parameters:

• sendbuf (BufSpecV | InPlace)

• recvbuf (BufSpecV)

• info (Info)

Return type:

Prequest

Alltoallw(sendbuf, recvbuf)

All to All Scatter/Gather General.

Send/recv data to/from all processes allowing the specification of different counts, displacements, and datatypes for each dest/source.

Parameters:

• sendbuf (BufSpecW | InPlace)

• recvbuf (BufSpecW)

Return type:

None

Alltoallw_init(sendbuf, recvbuf, info=INFO_NULL)

Persistent All to All Scatter/Gather General.

Parameters:

• sendbuf (BufSpecW | InPlace)

• recvbuf (BufSpecW)

• info (Info)

Return type:

Prequest

Attach_buffer(buf)

Attach a user-provided buffer for sending in buffered mode.

Parameters:

buf (Buffer | None)

Return type:

None

Barrier()

Barrier synchronization.

Return type:

None

Barrier_init(info=INFO_NULL)

Persistent Barrier.

Parameters:

info (Info)

Return type:

Prequest

Bcast(buf, root=0)

Broadcast data from one process to all other processes.

Parameters:

• buf (BufSpec)

• root (int)

Return type:

None

Bcast_init(buf, root=0, info=INFO_NULL)

Persistent Broadcast.

Parameters:

• buf (BufSpec)

• root (int)

• info (Info)

Return type:

Prequest

Bsend(buf, dest, tag=0)

Blocking send in buffered mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

None

Bsend_init(buf, dest, tag=0)

Persistent request for a send in buffered mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Request

Call_errhandler(errorcode)

Call the error handler installed on a communicator.

Parameters:

errorcode (int)

Return type:

None

Clone()

Clone an existing communicator.

Return type:

Self

Compare(comm)

Compare two communicators.

Parameters:

comm (Comm)

Return type:

int

Create(group)

Create communicator from group.

Parameters:

group (Group)

Return type:

Comm

classmethod Create_errhandler(errhandler_fn)

Create a new error handler for communicators.

Parameters:

errhandler_fn (Callable[[Comm, int], None])

Return type:

Errhandler

classmethod Create_keyval(copy_fn=None, delete_fn=None, nopython=False)

Create a new attribute key for communicators.

Parameters:

• copy_fn (Callable[[Comm, int, Any], Any] | None)

• delete_fn (Callable[[Comm, int, Any], None] | None)

• nopython (bool)

Return type:

int

Delete_attr(keyval)

Delete attribute value associated with a key.

Parameters:

keyval (int)

Return type:

None

Detach_buffer()

Remove an existing attached buffer.

Return type:

Buffer | None

Disconnect()

Disconnect from a communicator.

Return type:

None

Dup(info=None)

Duplicate a communicator.

Parameters:

info (Info | None)

Return type:

Self

Dup_with_info(info)

Duplicate a communicator with hints.

Parameters:

info (Info)

Return type:

Self

Flush_buffer()

Block until all buffered messages have been transmitted.

Return type:

None

Free()

Free a communicator.

Return type:

None

classmethod Free_keyval(keyval)

Free an attribute key for communicators.

Parameters:

keyval (int)

Return type:

int

Gather(sendbuf, recvbuf, root=0)

Gather data to one process from all other processes.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecB | None)

• root (int)

Return type:

None

Gather_init(sendbuf, recvbuf, root=0, info=INFO_NULL)

Persistent Gather.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecB | None)

• root (int)

• info (Info)

Return type:

Prequest

Gatherv(sendbuf, recvbuf, root=0)

Gather Vector.

Gather data to one process from all other processes providing different amounts of data and displacements.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecV | None)

• root (int)

Return type:

None

Gatherv_init(sendbuf, recvbuf, root=0, info=INFO_NULL)

Persistent Gather Vector.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecV | None)

• root (int)

• info (Info)

Return type:

Prequest

Get_attr(keyval)

Retrieve attribute value by key.

Parameters:

keyval (int)

Return type:

int | Any | None

Get_errhandler()

Get the error handler for a communicator.

Return type:

Errhandler

Get_failed()

Extract the group of failed processes.

Return type:

Group

Get_group()

Access the group associated with a communicator.

Return type:

Group

Get_info()

Return the current hints for a communicator.

Return type:

Info

Get_name()

Get the print name for this communicator.

Return type:

str

classmethod Get_parent()

Return the parent intercommunicator for this process.

Return type:

Intercomm

Get_rank()

Return the rank of this process in a communicator.

Return type:

int

Get_size()

Return the number of processes in a communicator.

Return type:

int

Get_topology()

Return the type of topology (if any) associated with a communicator.

Return type:

int

Iagree(flag)

Nonblocking agreement.

Parameters:

flag (Buffer)

Return type:

Request

Iallgather(sendbuf, recvbuf)

Nonblocking Gather to All.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecB)

Return type:

Request

Iallgatherv(sendbuf, recvbuf)

Nonblocking Gather to All Vector.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecV)

Return type:

Request

Iallreduce(sendbuf, recvbuf, op=SUM)

Nonblocking Reduce to All.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec)

• op (Op)

Return type:

Request

Ialltoall(sendbuf, recvbuf)

Nonblocking All to All Scatter/Gather.

Parameters:

• sendbuf (BufSpecB | InPlace)

• recvbuf (BufSpecB)

Return type:

Request

Ialltoallv(sendbuf, recvbuf)

Nonblocking All to All Scatter/Gather Vector.

Parameters:

• sendbuf (BufSpecV | InPlace)

• recvbuf (BufSpecV)

Return type:

Request

Ialltoallw(sendbuf, recvbuf)

Nonblocking All to All Scatter/Gather General.

Parameters:

• sendbuf (BufSpecW | InPlace)

• recvbuf (BufSpecW)

Return type:

Request

Ibarrier()

Nonblocking Barrier.

Return type:

Request

Ibcast(buf, root=0)

Nonblocking Broadcast.

Parameters:

• buf (BufSpec)

• root (int)

Return type:

Request

Ibsend(buf, dest, tag=0)

Nonblocking send in buffered mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Request

Idup(info=None)

Nonblocking duplicate a communicator.

Parameters:

info (Info | None)

Return type:

tuple[Self, Request]

Idup_with_info(info)

Nonblocking duplicate a communicator with hints.

Parameters:

info (Info)

Return type:

tuple[Self, Request]

Iflush_buffer()

Nonblocking flush for buffered messages.

Return type:

Request

Igather(sendbuf, recvbuf, root=0)

Nonblocking Gather.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecB | None)

• root (int)

Return type:

Request

Igatherv(sendbuf, recvbuf, root=0)

Nonblocking Gather Vector.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpecV | None)

• root (int)

Return type:

Request

Improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Nonblocking test for a matched message.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

Message | None

Iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Nonblocking test for a message.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

bool

Irecv(buf, source=ANY_SOURCE, tag=ANY_TAG)

Nonblocking receive.

Parameters:

• buf (BufSpec)

• source (int)

• tag (int)

Return type:

Request

Ireduce(sendbuf, recvbuf, op=SUM, root=0)

Nonblocking Reduce to Root.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec | None)

• op (Op)

• root (int)

Return type:

Request

Ireduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)

Nonblocking Reduce-Scatter (vector version).

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec)

• recvcounts (Sequence[int] | None)

• op (Op)

Return type:

Request

Ireduce_scatter_block(sendbuf, recvbuf, op=SUM)

Nonblocking Reduce-Scatter Block (regular, non-vector version).

Parameters:

• sendbuf (BufSpecB | InPlace)

• recvbuf (BufSpec | BufSpecB)

• op (Op)

Return type:

Request

Irsend(buf, dest, tag=0)

Nonblocking send in ready mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Request

Is_inter()

Return whether the communicator is an intercommunicator.

Return type:

bool

Is_intra()

Return whether the communicator is an intracommunicator.

Return type:

bool

Is_revoked()

Indicate whether the communicator has been revoked.

Return type:

bool

Iscatter(sendbuf, recvbuf, root=0)

Nonblocking Scatter.

Parameters:

• sendbuf (BufSpecB | None)

• recvbuf (BufSpec | InPlace)

• root (int)

Return type:

Request

Iscatterv(sendbuf, recvbuf, root=0)

Nonblocking Scatter Vector.

Parameters:

• sendbuf (BufSpecV | None)

• recvbuf (BufSpec | InPlace)

• root (int)

Return type:

Request

Isend(buf, dest, tag=0)

Nonblocking send.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Request

Isendrecv(sendbuf, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE, recvtag=ANY_TAG)

Nonblocking send and receive.

Parameters:

• sendbuf (BufSpec)

• dest (int)

• sendtag (int)

• recvbuf (BufSpec | None)

• source (int)

• recvtag (int)

Return type:

Request

Isendrecv_replace(buf, dest, sendtag=0, source=ANY_SOURCE, recvtag=ANY_TAG)

Send and receive a message.

Note

This function is guaranteed not to deadlock in situations where pairs of blocking sends and receives may deadlock.

Caution

A common mistake when using this function is to mismatch the tags with the source and destination ranks, which can result in deadlock.

Parameters:

• buf (BufSpec)

• dest (int)

• sendtag (int)

• source (int)

• recvtag (int)

Return type:

Request

Ishrink()

Nonblocking shrink a communicator to remove all failed processes.

Return type:

tuple[Comm, Request]

Issend(buf, dest, tag=0)

Nonblocking send in synchronous mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Request

classmethod Join(fd)

Interconnect two processes connected by a socket.

Parameters:

fd (int)

Return type:

Intercomm

Mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Blocking test for a matched message.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

Message

Precv_init(buf, partitions, source=ANY_SOURCE, tag=ANY_TAG, info=INFO_NULL)

Create request for a partitioned recv operation.

Parameters:

• buf (BufSpec)

• partitions (int)

• source (int)

• tag (int)

• info (Info)

Return type:

Prequest

Probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Blocking test for a message.

Note

This function blocks until the message arrives.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

Literal[True]

Psend_init(buf, partitions, dest, tag=0, info=INFO_NULL)

Create request for a partitioned send operation.

Parameters:

• buf (BufSpec)

• partitions (int)

• dest (int)

• tag (int)

• info (Info)

Return type:

Prequest

Recv(buf, source=ANY_SOURCE, tag=ANY_TAG, status=None)

Blocking receive.

Note

This function blocks until the message is received.

Parameters:

• buf (BufSpec)

• source (int)

• tag (int)

• status (Status | None)

Return type:

None

Recv_init(buf, source=ANY_SOURCE, tag=ANY_TAG)

Create a persistent request for a receive.

Parameters:

• buf (BufSpec)

• source (int)

• tag (int)

Return type:

Prequest

Reduce(sendbuf, recvbuf, op=SUM, root=0)

Reduce to Root.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec | None)

• op (Op)

• root (int)

Return type:

None

Reduce_init(sendbuf, recvbuf, op=SUM, root=0, info=INFO_NULL)

Persistent Reduce to Root.

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec | None)

• op (Op)

• root (int)

• info (Info)

Return type:

Prequest

Reduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)

Reduce-Scatter (vector version).

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec)

• recvcounts (Sequence[int] | None)

• op (Op)

Return type:

None

Reduce_scatter_block(sendbuf, recvbuf, op=SUM)

Reduce-Scatter Block (regular, non-vector version).

Parameters:

• sendbuf (BufSpecB | InPlace)

• recvbuf (BufSpec | BufSpecB)

• op (Op)

Return type:

None

Reduce_scatter_block_init(sendbuf, recvbuf, op=SUM, info=INFO_NULL)

Persistent Reduce-Scatter Block (regular, non-vector version).

Parameters:

• sendbuf (BufSpecB | InPlace)

• recvbuf (BufSpec | BufSpecB)

• op (Op)

• info (Info)

Return type:

Prequest

Reduce_scatter_init(sendbuf, recvbuf, recvcounts=None, op=SUM, info=INFO_NULL)

Persistent Reduce-Scatter (vector version).

Parameters:

• sendbuf (BufSpec | InPlace)

• recvbuf (BufSpec)

• recvcounts (Sequence[int] | None)

• op (Op)

• info (Info)

Return type:

Prequest

Revoke()

Revoke a communicator.

Return type:

None

Rsend(buf, dest, tag=0)

Blocking send in ready mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

None

Rsend_init(buf, dest, tag=0)

Persistent request for a send in ready mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Request

Scatter(sendbuf, recvbuf, root=0)

Scatter data from one process to all other processes.

Parameters:

• sendbuf (BufSpecB | None)

• recvbuf (BufSpec | InPlace)

• root (int)

Return type:

None

Scatter_init(sendbuf, recvbuf, root=0, info=INFO_NULL)

Persistent Scatter.

Parameters:

• sendbuf (BufSpecB | None)

• recvbuf (BufSpec | InPlace)

• root (int)

• info (Info)

Return type:

Prequest

Scatterv(sendbuf, recvbuf, root=0)

Scatter Vector.

Scatter data from one process to all other processes providing different amounts of data and displacements.

Parameters:

• sendbuf (BufSpecV | None)

• recvbuf (BufSpec | InPlace)

• root (int)

Return type:

None

Scatterv_init(sendbuf, recvbuf, root=0, info=INFO_NULL)

Persistent Scatter Vector.

Parameters:

• sendbuf (BufSpecV | None)

• recvbuf (BufSpec | InPlace)

• root (int)

• info (Info)

Return type:

Prequest

Send(buf, dest, tag=0)

Blocking send.

Note

This function may block until the message is received. Whether Send blocks or not depends on several factors and is implementation dependent.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

None

Send_init(buf, dest, tag=0)

Create a persistent request for a standard send.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Prequest

Sendrecv(sendbuf, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE, recvtag=ANY_TAG, status=None)

Send and receive a message.

Note

This function is guaranteed not to deadlock in situations where pairs of blocking sends and receives may deadlock.

Caution

A common mistake when using this function is to mismatch the tags with the source and destination ranks, which can result in deadlock.

Parameters:

• sendbuf (BufSpec)

• dest (int)

• sendtag (int)

• recvbuf (BufSpec | None)

• source (int)

• recvtag (int)

• status (Status | None)

Return type:

None

Sendrecv_replace(buf, dest, sendtag=0, source=ANY_SOURCE, recvtag=ANY_TAG, status=None)

Send and receive a message.

Note

This function is guaranteed not to deadlock in situations where pairs of blocking sends and receives may deadlock.

Caution

A common mistake when using this function is to mismatch the tags with the source and destination ranks, which can result in deadlock.

Parameters:

• buf (BufSpec)

• dest (int)

• sendtag (int)

• source (int)

• recvtag (int)

• status (Status | None)

Return type:

None

Set_attr(keyval, attrval)

Store attribute value associated with a key.

Parameters:

• keyval (int)

• attrval (Any)

Return type:

None

Set_errhandler(errhandler)

Set the error handler for a communicator.

Parameters:

errhandler (Errhandler)

Return type:

None

Set_info(info)

Set new values for the hints associated with a communicator.

Parameters:

info (Info)

Return type:

None

Set_name(name)

Set the print name for this communicator.

Parameters:

name (str)

Return type:

None

Shrink()

Shrink a communicator to remove all failed processes.

Return type:

Comm

Split(color=0, key=0)

Split communicator by color and key.

Parameters:

• color (int)

• key (int)

Return type:

Comm

Split_type(split_type, key=0, info=INFO_NULL)

Split communicator by split type.

Parameters:

• split_type (int)

• key (int)

• info (Info)

Return type:

Comm

Ssend(buf, dest, tag=0)

Blocking send in synchronous mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

None

Ssend_init(buf, dest, tag=0)

Persistent request for a send in synchronous mode.

Parameters:

• buf (BufSpec)

• dest (int)

• tag (int)

Return type:

Request

allgather(sendobj)

Gather to All.

Parameters:

sendobj (Any)

Return type:

list[Any]

allreduce(sendobj, op=SUM)

Reduce to All.

Parameters:

• sendobj (Any)

• op (Op | Callable[[Any, Any], Any])

Return type:

Any

alltoall(sendobj)

All to All Scatter/Gather.

Parameters:

sendobj (Sequence[Any])

Return type:

list[Any]

barrier()

Barrier synchronization.

Note

This method is equivalent to Barrier.

Return type:

None

bcast(obj, root=0)

Broadcast.

Parameters:

• obj (Any)

• root (int)

Return type:

Any

bsend(obj, dest, tag=0)

Send in buffered mode.

Parameters:

• obj (Any)

• dest (int)

• tag (int)

Return type:

None

classmethod f2py(arg)

Parameters:

arg (int)

Return type:

Comm

free()

Call Free if not null or predefined.

Return type:

None

classmethod fromhandle(handle)

Create object from MPI handle.

Parameters:

handle (int)

Return type:

Comm

gather(sendobj, root=0)

Gather.

Parameters:

• sendobj (Any)

• root (int)

Return type:

list[Any] | None

ibsend(obj, dest, tag=0)

Nonblocking send in buffered mode.

Parameters:

• obj (Any)

• dest (int)

• tag (int)

Return type:

Request

improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Nonblocking test for a matched message.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

Message | None

iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Nonblocking test for a message.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

bool

irecv(buf=None, source=ANY_SOURCE, tag=ANY_TAG)

Nonblocking receive.

Parameters:

• buf (Buffer | None)

• source (int)

• tag (int)

Return type:

Request

isend(obj, dest, tag=0)

Nonblocking send.

Parameters:

• obj (Any)

• dest (int)

• tag (int)

Return type:

Request

issend(obj, dest, tag=0)

Nonblocking send in synchronous mode.

Parameters:

• obj (Any)

• dest (int)

• tag (int)

Return type:

Request

mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Blocking test for a matched message.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

Message

probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)

Blocking test for a message.

Parameters:

• source (int)

• tag (int)

• status (Status | None)

Return type:

Literal[True]

py2f()

Return type:

int

recv(buf=None, source=ANY_SOURCE, tag=ANY_TAG, status=None)

Receive.

Parameters:

• buf (Buffer | None)

• source (int)

• tag (int)

• status (Status | None)

Return type:

Any

reduce(sendobj, op=SUM, root=0)

Reduce to Root.

Parameters:

• sendobj (Any)

• op (Op | Callable[[Any, Any], Any])

• root (int)

Return type:

Any | None

scatter(sendobj, root=0)

Scatter.

Parameters:

• sendobj (Sequence[Any] | None)

• root (int)

Return type:

Any

send(obj, dest, tag=0)

Send in standard mode.

Parameters:

• obj (Any)

• dest (int)

• tag (int)

Return type:

None

sendrecv(sendobj, dest, sendtag=0, recvbuf=None, source=ANY_SOURCE, recvtag=ANY_TAG, status=None)

Send and Receive.

Parameters:

• sendobj (Any)

• dest (int)

• sendtag (int)

• recvbuf (Buffer | None)

• source (int)

• recvtag (int)

• status (Status | None)

Return type:

Any

ssend(obj, dest, tag=0)

Send in synchronous mode.

Parameters:

• obj (Any)

• dest (int)

• tag (int)

Return type:

None

Attributes Documentation

group

Group.

handle

MPI handle.

info

Info hints.

is_inter

Is intercommunicator.

is_intra

Is intracommunicator.

is_topo

Is a topology.

name

Print name.

rank

Rank of this process.

size

Number of processes.

topology

Topology type.