ScaLAPACK compatibility / BLACS helpers

Data types and helper functions for BLACS. More...

Functions
void	starneig_blacs_pinfo (int *my_rank, int *rank_count)
	Queries process rank information. More...
int	starneig_blacs_get (starneig_blacs_context_t context, starneig_blacs_query_id_t query)
	Returns BLACS context's internal defaults. More...
starneig_blacs_context_t	starneig_blacs_gridinit (starneig_blacs_context_t system_context, char *order, int rows, int cols)
	Initializes a BLACS process grid. More...
void	starneig_blacs_gridinfo (starneig_blacs_context_t context, int *rows, int *cols, int *row, int *col)
	Queries BLACS process grid information. More...
void	starneig_blacs_pcoord (starneig_blacs_context_t context, int process, int *row, int *col)
	Queries BLACS process grid coordinates. More...
void	starneig_blacs_gridexit (starneig_blacs_context_t context)
	Releases process grid specific resources. More...
void	starneig_blacs_exit (int cont)
	Releases all contexts and related resources. More...
int	starneig_blacs_numroc (int n, int nb, int iproc, int isrcproc, int nprocs)
	Computes the number of matrix rows/columns owned by a given process. More...
int	starneig_blacs_descinit (struct starneig_blacs_descr *descr, int m, int n, int sm, int sn, int irsrc, int icsrc, starneig_blacs_context_t context, int ld)
	Initializes a BLACS descriptor. More...

Query indeces
typedef int	starneig_blacs_query_id_t
	Data type for blacs_get() function query id.
#define	STARNEIG_BLACS_GET_DEFAULT_CONTEXT   0
	Query id for getting the default system context.

Detailed Description

Data types and helper functions for BLACS.

Function Documentation

starneig_blacs_pinfo()

void starneig_blacs_pinfo	(	int *	my_rank,
		int *	rank_count
	)

Queries process rank information.

Parameters

[out]	my_rank	An unique process id (rank).
[out]	rank_count	The total number of processes (ranks) available.

starneig_blacs_get()

int starneig_blacs_get	(	starneig_blacs_context_t	context,
		starneig_blacs_query_id_t	query
	)

Returns BLACS context's internal defaults.

Parameters

[in]	context	The BLACS context.
[in]	query	The query id.

Returns

The internal default value that matches the given query id.

starneig_blacs_gridinit()

starneig_blacs_context_t starneig_blacs_gridinit	(	starneig_blacs_context_t	system_context,
		char *	order,
		int	rows,
		int	cols
	)

Initializes a BLACS process grid.

Parameters

[in]	system_context	The system BLACS context to be used in creating the process grid.
[in]	order	The process mapping order. "R" : Use row-major natural ordering. "C" : Use column-major natural ordering. ELSE: Use row-major natural ordering.
[in]	rows	The number of rows in the process grid.
[in]	cols	The number of columns in the process grid.

Returns

A handle to the created BLACS context.

starneig_blacs_gridinfo()

void starneig_blacs_gridinfo	(	starneig_blacs_context_t	context,
		int *	rows,
		int *	cols,
		int *	row,
		int *	col
	)

Queries BLACS process grid information.

Parameters

[in]	context	The BLACS context.
[out]	rows	The number of rows in the process grid.
[out]	cols	The number of columns in the process grid.
[out]	row	The row coordinate of the calling process.
[out]	col	The column coordinate of the calling process.

starneig_blacs_pcoord()

void starneig_blacs_pcoord	(	starneig_blacs_context_t	context,
		int	process,
		int *	row,
		int *	col
	)

Queries BLACS process grid coordinates.

Parameters

[in]	context	The BLACS context.
[in]	process	The process id (rank).
[out]	row	The row coordinate of the process.
[out]	col	The column coordinate of the process.

starneig_blacs_gridexit()

void starneig_blacs_gridexit

(

starneig_blacs_context_t

context

)

Releases process grid specific resources.

Parameters

[in]

context

The BLACS context.

starneig_blacs_exit()

void starneig_blacs_exit

(

int

cont

)

Releases all contexts and related resources.

Parameters

[in]

cont

The continue flag.

starneig_blacs_numroc()

int starneig_blacs_numroc	(	int	n,
		int	nb,
		int	iproc,
		int	isrcproc,
		int	nprocs
	)

Computes the number of matrix rows/columns owned by a given process.

Parameters

[in]	n	The number of rows/columns in the distributed matrix.
[in]	nb	The block size.
[in]	iproc	The coordinate of the process whose local array row or column is to be determined.
[in]	isrcproc	The coordinate of the process that possesses the first row or column of the distributed matrix.
[in]	nprocs	The total number processes over which the matrix is distributed.

Returns

The number of rows/columns owned by the process.

starneig_blacs_descinit()

int starneig_blacs_descinit	(	struct starneig_blacs_descr *	descr,
		int	m,
		int	n,
		int	sm,
		int	sn,
		int	irsrc,
		int	icsrc,
		starneig_blacs_context_t	context,
		int	ld
	)

Initializes a BLACS descriptor.

Parameters

[out]	descr	The matrix descriptor.
[in]	m	The number of rows in the matrix.
[in]	n	The number of columns in the matrix.
[in]	sm	The number of rows in a distributed block.
[in]	sn	The number of columns in a distributed block.
[in]	irsrc	The process grid row over which the first row is distributed.
[in]	icsrc	The process grid column over which the first column is distributed.
[in]	context	The BLACS context.
[in]	ld	The local array leading dimension.

Returns

Zero if the initialization was successful, non-zero otherwise.