methods to split tall-and-skinny matrices along longest dimension. Basically, we are splitting process grid and each subgrid holds its own DBM matrix. More...

Data Types
interface	dbt_tas_mp_comm

Functions/Subroutines
subroutine, public	dbt_tas_create_split_rows_or_cols (split_info, mp_comm, ngroup, igroup, split_rowcol, own_comm)
	split mpi grid by rows or columns
type(mp_cart_type) function, public	dbt_tas_mp_comm (mp_comm, split_rowcol, nsplit)
	Create default cartesian process grid that is consistent with default split heuristic of dbt_tas_create_split.
integer function, dimension(2), public	dbt_tas_mp_dims (numproc, split_rowcol, nsplit)
	Get optimal process grid dimensions consistent with dbt_tas_create_split.
subroutine, public	dbt_tas_create_split (split_info, mp_comm, split_rowcol, nsplit, own_comm, opt_nsplit)
	Split Cartesian process grid using a default split heuristic.
logical function, public	accept_pgrid_dims (dims, relative)
	Whether to accept proposed process grid dimensions (based on ratio of dimensions).
subroutine, public	dbt_tas_get_split_info (info, mp_comm, nsplit, igroup, mp_comm_group, split_rowcol, pgrid_offset)
	Get info on split.
subroutine, public	dbt_tas_release_info (split_info)
	...
subroutine, public	dbt_tas_info_hold (split_info)
	...
subroutine, public	world_to_group_proc_map (iproc, pdims, split_rowcol, pgrid_split_size, igroup, pdims_group, iproc_group)
	map global process info to group
subroutine, public	group_to_world_proc_map (iproc, pdims, split_rowcol, pgrid_split_size, igroup, iproc_group)
	map local process info to global info
subroutine, public	dbt_index_local_to_global (info, dist, row_group, column_group, row, column)
	map group local block index to global matrix index
subroutine, public	dbt_index_global_to_local (info, dist, row, column, row_group, column_group)
	map global block index to group local index
subroutine, public	group_to_mrowcol (info, rowcol_dist, igroup, rowcols)
	maps a process subgroup to matrix rows/columns
subroutine, public	dbt_tas_set_strict_split (info)
	freeze current split factor such that it is never changed during multiplication

Variables
integer, parameter, public	rowsplit = 1
integer, parameter, public	colsplit = 2
real(dp), parameter, public	default_pdims_accept_ratio = 1.2_dp
real(dp), parameter, public	default_nsplit_accept_ratio = 3.0_dp

Detailed Description

methods to split tall-and-skinny matrices along longest dimension. Basically, we are splitting process grid and each subgrid holds its own DBM matrix.

Author: Patrick Seewald

Function/Subroutine Documentation

◆ dbt_tas_create_split_rows_or_cols()

subroutine, public dbt_tas_split::dbt_tas_create_split_rows_or_cols	(	type(dbt_tas_split_info), intent(out)	split_info,
		type(mp_cart_type), intent(in)	mp_comm,
		integer, intent(inout)	ngroup,
		integer, intent(in)	igroup,
		integer, intent(in)	split_rowcol,
		logical, intent(in), optional	own_comm )

split mpi grid by rows or columns

Parameters

split_info	...
mp_comm	global mpi communicator with a 2d cartesian grid
ngroup	number of groups
igroup	my group ID
split_rowcol	split rows or columns
own_comm	Whether split_info should own communicator

Author: Patrick Seewald

Definition at line 71 of file dbt_tas_split.F.

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◆ dbt_tas_mp_comm()

type(mp_cart_type) function, public dbt_tas_split::dbt_tas_mp_comm	(	class(mp_comm_type), intent(in)	mp_comm,
		integer, intent(in)	split_rowcol,
		integer, intent(in)	nsplit )

Create default cartesian process grid that is consistent with default split heuristic of dbt_tas_create_split.

Parameters

mp_comm	...
split_rowcol	...
nsplit	...

Returns: new communicator

Author: Patrick Seewald

Definition at line 154 of file dbt_tas_split.F.

◆ dbt_tas_mp_dims()

integer function, dimension(2), public dbt_tas_split::dbt_tas_mp_dims	(	integer, intent(in)	numproc,
		integer, intent(in)	split_rowcol,
		integer, intent(in)	nsplit )

Get optimal process grid dimensions consistent with dbt_tas_create_split.

Parameters

numproc	...
split_rowcol	...
nsplit	...

Returns: ...

Author: Patrick Seewald

Definition at line 183 of file dbt_tas_split.F.

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◆ dbt_tas_create_split()

subroutine, public dbt_tas_split::dbt_tas_create_split	(	type(dbt_tas_split_info), intent(out)	split_info,
		type(mp_cart_type), intent(in)	mp_comm,
		integer, intent(in)	split_rowcol,
		integer, intent(in)	nsplit,
		logical, intent(in), optional	own_comm,
		logical, intent(in), optional	opt_nsplit )

Split Cartesian process grid using a default split heuristic.

Parameters

split_info	object storing all data corresponding to split, submatrices and parallelization
mp_comm	MPI communicator with associated cartesian grid
split_rowcol	split rows or columns
nsplit	desired split factor, set to 0 if split factor of exactly 1 is required
own_comm	whether split_info should own communicator
opt_nsplit	whether nsplit should be optimized to process grid

Author: Patrick Seewald

Definition at line 332 of file dbt_tas_split.F.

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◆ accept_pgrid_dims()

logical function, public dbt_tas_split::accept_pgrid_dims	(	integer, dimension(2), intent(in)	dims,
		logical, intent(in)	relative )

Whether to accept proposed process grid dimensions (based on ratio of dimensions).

Parameters

dims	...
relative	...

Returns: ...

Author: Patrick Seewald

Definition at line 399 of file dbt_tas_split.F.

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◆ dbt_tas_get_split_info()

subroutine, public dbt_tas_split::dbt_tas_get_split_info	(	type(dbt_tas_split_info), intent(in)	info,
		type(mp_cart_type), intent(out), optional	mp_comm,
		integer, intent(out), optional	nsplit,
		integer, intent(out), optional	igroup,
		type(mp_cart_type), intent(out), optional	mp_comm_group,
		integer, intent(out), optional	split_rowcol,
		integer, dimension(2), intent(out), optional	pgrid_offset )

Get info on split.

Parameters

info	...
mp_comm	communicator (global process grid)
nsplit	split factor
igroup	which group do I belong to
mp_comm_group	subgroup communicator (group-local process grid)
split_rowcol	split rows or columns
pgrid_offset	group-local offset in process grid

Author: Patrick Seewald

Definition at line 426 of file dbt_tas_split.F.

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◆ dbt_tas_release_info()

subroutine, public dbt_tas_split::dbt_tas_release_info ( type(dbt_tas_split_info), intent(inout) split_info )

...

Parameters

split_info ...

Author: Patrick Seewald

Definition at line 456 of file dbt_tas_split.F.

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◆ dbt_tas_info_hold()

subroutine, public dbt_tas_split::dbt_tas_info_hold ( type(dbt_tas_split_info), intent(in) split_info )

...

Parameters

split_info ...

Author: Patrick Seewald

Definition at line 491 of file dbt_tas_split.F.

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◆ world_to_group_proc_map()

subroutine, public dbt_tas_split::world_to_group_proc_map	(	integer, intent(in)	iproc,
		integer, dimension(2), intent(in)	pdims,
		integer, intent(in)	split_rowcol,
		integer, intent(in)	pgrid_split_size,
		integer, intent(out)	igroup,
		integer, dimension(2), intent(out), optional	pdims_group,
		integer, intent(out), optional	iproc_group )

map global process info to group

Parameters

iproc	global process ID
pdims	global process dimensions
split_rowcol	split rows or column
pgrid_split_size	how many process rows/cols per group
igroup	group ID
pdims_group	local process grid dimensions
iproc_group	group local process ID

Author: Patrick Seewald

Definition at line 514 of file dbt_tas_split.F.

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◆ group_to_world_proc_map()

subroutine, public dbt_tas_split::group_to_world_proc_map	(	integer, intent(out)	iproc,
		integer, dimension(2), intent(in)	pdims,
		integer, intent(in)	split_rowcol,
		integer, intent(in)	pgrid_split_size,
		integer, intent(in)	igroup,
		integer, intent(in)	iproc_group )

map local process info to global info

Parameters

iproc	global process id
pdims	global process grid dimensions
split_rowcol	split rows or colum
pgrid_split_size	how many process rows/cols per group
igroup	group ID
iproc_group	local process ID

Author: Patrick Seewald

Definition at line 554 of file dbt_tas_split.F.

◆ dbt_index_local_to_global()

subroutine, public dbt_tas_split::dbt_index_local_to_global	(	type(dbt_tas_split_info), intent(in)	info,
		type(dbt_tas_distribution_type), intent(in)	dist,
		integer, intent(in), optional	row_group,
		integer, intent(in), optional	column_group,
		integer(kind=int_8), intent(out), optional	row,
		integer(kind=int_8), intent(out), optional	column )

map group local block index to global matrix index

Parameters

info	...
dist	...
row_group	group local row block index
column_group	group local column block index
row	global block row
column	global block column

Author: Patrick Seewald

Definition at line 591 of file dbt_tas_split.F.

◆ dbt_index_global_to_local()

subroutine, public dbt_tas_split::dbt_index_global_to_local	(	type(dbt_tas_split_info), intent(in)	info,
		type(dbt_tas_distribution_type), intent(in)	dist,
		integer(kind=int_8), intent(in), optional	row,
		integer(kind=int_8), intent(in), optional	column,
		integer, intent(out), optional	row_group,
		integer, intent(out), optional	column_group )

map global block index to group local index

Parameters

info	...
dist	...
row	...
column	...
row_group	...
column_group	...

Author: Patrick Seewald

Definition at line 621 of file dbt_tas_split.F.

◆ group_to_mrowcol()

subroutine, public dbt_tas_split::group_to_mrowcol	(	type(dbt_tas_split_info), intent(in)	info,
		class(dbt_tas_distribution), intent(in)	rowcol_dist,
		integer, intent(in)	igroup,
		integer(kind=int_8), dimension(:), intent(out), allocatable	rowcols )

maps a process subgroup to matrix rows/columns

Parameters

info	...
rowcol_dist	...
igroup	group ID
rowcols	rows/ columns on this group

Author: Patrick Seewald

Definition at line 677 of file dbt_tas_split.F.

◆ dbt_tas_set_strict_split()

subroutine, public dbt_tas_split::dbt_tas_set_strict_split ( type(dbt_tas_split_info), intent(inout) info )

freeze current split factor such that it is never changed during multiplication

Parameters

info ...

Author: Patrick Seewald

Definition at line 712 of file dbt_tas_split.F.

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Variable Documentation

◆ rowsplit

integer, parameter, public dbt_tas_split::rowsplit = 1

Definition at line 50 of file dbt_tas_split.F.

◆ colsplit

integer, parameter, public dbt_tas_split::colsplit = 2

Definition at line 50 of file dbt_tas_split.F.

◆ default_pdims_accept_ratio

real(dp), parameter, public dbt_tas_split::default_pdims_accept_ratio = 1.2_dp

Definition at line 51 of file dbt_tas_split.F.

◆ default_nsplit_accept_ratio

real(dp), parameter, public dbt_tas_split::default_nsplit_accept_ratio = 3.0_dp

Definition at line 52 of file dbt_tas_split.F.

Data Types

Functions/Subroutines

Variables

Detailed Description

Function/Subroutine Documentation

◆ dbt_tas_create_split_rows_or_cols()

◆ dbt_tas_mp_comm()

◆ dbt_tas_mp_dims()

◆ dbt_tas_create_split()

◆ accept_pgrid_dims()

◆ dbt_tas_get_split_info()

◆ dbt_tas_release_info()

◆ dbt_tas_info_hold()

◆ world_to_group_proc_map()

◆ group_to_world_proc_map()

◆ dbt_index_local_to_global()

◆ dbt_index_global_to_local()

◆ group_to_mrowcol()

◆ dbt_tas_set_strict_split()

Variable Documentation

◆ rowsplit

◆ colsplit

◆ default_pdims_accept_ratio

◆ default_nsplit_accept_ratio