mpi4py.MPI.Datatype

class mpi4py.MPI.Datatype

Bases: object

Datatype object.

static __new__(cls, datatype=None)

Parameters:: datatype (Datatype | None) –
Return type:: Datatype

Methods Summary

`Commit`()	Commit the datatype.
`Create_contiguous`(count)	Create a contiguous datatype.
`Create_darray`(size, rank, gsizes, distribs, ...)	Create a datatype for a distributed array on Cartesian process grids.
`Create_f90_complex`(p, r)	Return a bounded complex datatype.
`Create_f90_integer`(r)	Return a bounded integer datatype.
`Create_f90_real`(p, r)	Return a bounded real datatype.
`Create_hindexed`(blocklengths, displacements)	Create an indexed datatype.
`Create_hindexed_block`(blocklength, displacements)	Create an indexed datatype with constant-sized blocks.
`Create_hvector`(count, blocklength, stride)	Create a vector (strided) datatype with stride in bytes.
`Create_indexed`(blocklengths, displacements)	Create an indexed datatype.
`Create_indexed_block`(blocklength, displacements)	Create an indexed datatype with constant-sized blocks.
`Create_keyval`([copy_fn, delete_fn, nopython])	Create a new attribute key for datatypes.
`Create_resized`(lb, extent)	Create a datatype with a new lower bound and extent.
`Create_struct`(blocklengths, displacements, ...)	Create a general composite (struct) datatype.
`Create_subarray`(sizes, subsizes, starts[, order])	Create a datatype for a subarray of a multidimensional array.
`Create_vector`(count, blocklength, stride)	Create a vector (strided) datatype.
`Delete_attr`(keyval)	Delete attribute value associated with a key.
`Dup`()	Duplicate a datatype.
`Free`()	Free the datatype.
`Free_keyval`(keyval)	Free an attribute key for datatypes.
`Get_attr`(keyval)	Retrieve attribute value by key.
`Get_contents`()	Return the input arguments used to create a datatype.
`Get_envelope`()	Return the number of input arguments used to create a datatype.
`Get_extent`()	Return lower bound and extent of datatype.
`Get_name`()	Get the print name for this datatype.
`Get_size`()	Return the number of bytes occupied by entries in the datatype.
`Get_true_extent`()	Return the true lower bound and extent of a datatype.
`Match_size`(typeclass, size)	Find a datatype matching a specified size in bytes.
`Pack`(inbuf, outbuf, position, comm)	Pack into contiguous memory according to datatype.
`Pack_external`(datarep, inbuf, outbuf, position)	Pack into contiguous memory according to datatype.
`Pack_external_size`(datarep, count)	Determine the amount of space needed to pack a message.
`Pack_size`(count, comm)	Determine the amount of space needed to pack a message.
`Set_attr`(keyval, attrval)	Store attribute value associated with a key.
`Set_name`(name)	Set the print name for this datatype.
`Unpack`(inbuf, position, outbuf, comm)	Unpack from contiguous memory according to datatype.
`Unpack_external`(datarep, inbuf, position, outbuf)	Unpack from contiguous memory according to datatype.
`decode`()	Convenience method for decoding a datatype.
`f2py`(arg)
`fromcode`(code)	Get predefined MPI datatype from character code or type string.
`fromhandle`(handle)	Create object from MPI handle.
`py2f`()
`tocode`()	Get character code or type string from predefined MPI datatype.

Attributes Summary

`combiner`	Combiner.
`contents`	Contents.
`envelope`	Envelope.
`extent`	Extent.
`handle`	MPI handle.
`is_named`	Is a named datatype.
`is_predefined`	Is a predefined datatype.
`lb`	Lower bound.
`name`	Print name.
`size`	Size (in bytes).
`true_extent`	True extent.
`true_lb`	True lower bound.
`true_ub`	True upper bound.
`typechar`	Character code.
`typestr`	Type string.
`ub`	Upper bound.

Methods Documentation

Commit()

Commit the datatype.

Return type:: Self

Create_contiguous(count)

Create a contiguous datatype.

Parameters:: count (int) –
Return type:: Self

Create_darray(size, rank, gsizes, distribs, dargs, psizes, order=ORDER_C)

Create a datatype for a distributed array on Cartesian process grids.

Parameters:

size (int) –
rank (int) –
gsizes (Sequence[int]) –
distribs (Sequence[int]) –
dargs (Sequence[int]) –
psizes (Sequence[int]) –
order (int) –

Return type:

Self

classmethod Create_f90_complex(p, r)

Return a bounded complex datatype.

Parameters:

p (int) –
r (int) –

Return type:

Self

classmethod Create_f90_integer(r)

Return a bounded integer datatype.

Parameters:: r (int) –
Return type:: Self

classmethod Create_f90_real(p, r)

Return a bounded real datatype.

Parameters:

p (int) –
r (int) –

Return type:

Self

Create_hindexed(blocklengths, displacements)

Create an indexed datatype.

Note

Displacements are measured in bytes.

Parameters:

blocklengths (Sequence[int]) –
displacements (Sequence[int]) –

Return type:

Self

Create_hindexed_block(blocklength, displacements)

Create an indexed datatype with constant-sized blocks.

Note

Displacements are measured in bytes.

Parameters:

blocklength (int) –
displacements (Sequence[int]) –

Return type:

Self

Create_hvector(count, blocklength, stride)

Create a vector (strided) datatype with stride in bytes.

Parameters:

count (int) –
blocklength (int) –
stride (int) –

Return type:

Self

Create_indexed(blocklengths, displacements)

Create an indexed datatype.

Parameters:

blocklengths (Sequence[int]) –
displacements (Sequence[int]) –

Return type:

Self

Create_indexed_block(blocklength, displacements)

Create an indexed datatype with constant-sized blocks.

Parameters:

blocklength (int) –
displacements (Sequence[int]) –

Return type:

Self

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

Create a new attribute key for datatypes.

Parameters:

copy_fn (Callable[[Datatype, int, Any], Any] | None) –
delete_fn (Callable[[Datatype, int, Any], None] | None) –
nopython (bool) –

Return type:

int

Create_resized(lb, extent)

Create a datatype with a new lower bound and extent.

Parameters:

lb (int) –
extent (int) –

Return type:

Self

classmethod Create_struct(blocklengths, displacements, datatypes)

Create a general composite (struct) datatype.

Note

Displacements are measured in bytes.

Parameters:

blocklengths (Sequence[int]) –
displacements (Sequence[int]) –
datatypes (Sequence[Datatype]) –

Return type:

Self

Create_subarray(sizes, subsizes, starts, order=ORDER_C)

Create a datatype for a subarray of a multidimensional array.

Parameters:

sizes (Sequence[int]) –
subsizes (Sequence[int]) –
starts (Sequence[int]) –
order (int) –

Return type:

Self

Create_vector(count, blocklength, stride)

Create a vector (strided) datatype.

Parameters:

count (int) –
blocklength (int) –
stride (int) –

Return type:

Self

Delete_attr(keyval)

Delete attribute value associated with a key.

Parameters:: keyval (int) –
Return type:: None

Dup()

Duplicate a datatype.

Return type:: Self

Free()

Free the datatype.

Return type:: None

classmethod Free_keyval(keyval)

Free an attribute key for datatypes.

Parameters:: keyval (int) –
Return type:: int

Get_attr(keyval)

Retrieve attribute value by key.

Parameters:: keyval (int) –
Return type:: int | Any | None

Get_contents()

Return the input arguments used to create a datatype.

Return type:: tuple[list[int], list[int], list[int], list[Datatype]]

Get_envelope()

Return the number of input arguments used to create a datatype.

Return type:: tuple[int, int, int, int, int]

Get_extent()

Return lower bound and extent of datatype.

Return type:: tuple[int, int]

Get_name()

Get the print name for this datatype.

Return type:: str

Get_size()

Return the number of bytes occupied by entries in the datatype.

Return type:: int

Get_true_extent()

Return the true lower bound and extent of a datatype.

Return type:: tuple[int, int]

classmethod Match_size(typeclass, size)

Find a datatype matching a specified size in bytes.

Parameters:

typeclass (int) –
size (int) –

Return type:

Self

Pack(inbuf, outbuf, position, comm)

Pack into contiguous memory according to datatype.

Parameters:

inbuf (BufSpec) –
outbuf (BufSpec) –
position (int) –
comm (Comm) –

Return type:

int

Pack_external(datarep, inbuf, outbuf, position)

Pack into contiguous memory according to datatype.

Uses the portable data representation external32.

Parameters:

datarep (str) –
inbuf (BufSpec) –
outbuf (BufSpec) –
position (int) –

Return type:

int

Pack_external_size(datarep, count)

Determine the amount of space needed to pack a message.

Uses the portable data representation external32.

Note

Returns an upper bound measured in bytes.

Parameters:

datarep (str) –
count (int) –

Return type:

int

Pack_size(count, comm)

Determine the amount of space needed to pack a message.

Note

Returns an upper bound measured in bytes.

Parameters:

count (int) –
comm (Comm) –

Return type:

int

Set_attr(keyval, attrval)

Store attribute value associated with a key.

Parameters:

keyval (int) –
attrval (Any) –

Return type:

None

Set_name(name)

Set the print name for this datatype.

Parameters:: name (str) –
Return type:: None

Unpack(inbuf, position, outbuf, comm)

Unpack from contiguous memory according to datatype.

Parameters:

inbuf (BufSpec) –
position (int) –
outbuf (BufSpec) –
comm (Comm) –

Return type:

int

Unpack_external(datarep, inbuf, position, outbuf)

Unpack from contiguous memory according to datatype.

Uses the portable data representation external32.

Parameters:

datarep (str) –
inbuf (BufSpec) –
position (int) –
outbuf (BufSpec) –

Return type:

int

decode()

Convenience method for decoding a datatype.

Return type:: tuple[Datatype, str, dict[str, Any]]

classmethod f2py(arg)

Parameters:: arg (int) –
Return type:: Datatype

classmethod fromcode(code)

Get predefined MPI datatype from character code or type string.

Parameters:: code (str) –
Return type:: Datatype

classmethod fromhandle(handle)

Create object from MPI handle.

Parameters:: handle (int) –
Return type:: Datatype

py2f()

Return type:: int

tocode()

Get character code or type string from predefined MPI datatype.

Return type:: str

Attributes Documentation

combiner: Combiner.

contents: Contents.

envelope: Envelope.

extent: Extent.

handle: MPI handle.

is_named: Is a named datatype.

is_predefined: Is a predefined datatype.

lb: Lower bound.

name: Print name.

size: Size (in bytes).

true_extent: True extent.

true_lb: True lower bound.

true_ub: True upper bound.

typechar: Character code.

typestr: Type string.

ub: Upper bound.