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ScaLAPACK
2.0.2
ScaLAPACK: Scalable Linear Algebra PACKage
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ScaLAPACK
2.0.2
ScaLAPACK: Scalable Linear Algebra PACKage
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#include "pblas.h"#include "PBpblas.h"#include "PBtools.h"#include "PBblacs.h"#include "PBblas.h"Go to the source code of this file.
Functions/Subroutines | |
| void | pcaxpy_ (int *N, float *ALPHA, float *X, int *IX, int *JX, int *DESCX, int *INCX, float *Y, int *IY, int *JY, int *DESCY, int *INCY) |
| void pcaxpy_ | ( | int * | N, |
| float * | ALPHA, | ||
| float * | X, | ||
| int * | IX, | ||
| int * | JX, | ||
| int * | DESCX, | ||
| int * | INCX, | ||
| float * | Y, | ||
| int * | IY, | ||
| int * | JY, | ||
| int * | DESCY, | ||
| int * | INCY | ||
| ) |
Definition at line 25 of file pcaxpy_.c.
{
/*
* Purpose
* =======
*
* PCAXPY adds one subvector to another,
*
* sub( Y ) := sub( Y ) + alpha * sub( X ),
*
* where
*
* sub( X ) denotes X(IX,JX:JX+N-1) if INCX = M_X,
* X(IX:IX+N-1,JX) if INCX = 1 and INCX <> M_X, and,
*
* sub( Y ) denotes Y(IY,JY:JY+N-1) if INCY = M_Y,
* Y(IY:IY+N-1,JY) if INCY = 1 and INCY <> M_Y.
*
* Notes
* =====
*
* A description vector is associated with each 2D block-cyclicly dis-
* tributed matrix. This vector stores the information required to
* establish the mapping between a matrix entry and its corresponding
* process and memory location.
*
* In the following comments, the character _ should be read as
* "of the distributed matrix". Let A be a generic term for any 2D
* block cyclicly distributed matrix. Its description vector is DESC_A:
*
* NOTATION STORED IN EXPLANATION
* ---------------- --------------- ------------------------------------
* DTYPE_A (global) DESCA[ DTYPE_ ] The descriptor type.
* CTXT_A (global) DESCA[ CTXT_ ] The BLACS context handle, indicating
* the NPROW x NPCOL BLACS process grid
* A is distributed over. The context
* itself is global, but the handle
* (the integer value) may vary.
* M_A (global) DESCA[ M_ ] The number of rows in the distribu-
* ted matrix A, M_A >= 0.
* N_A (global) DESCA[ N_ ] The number of columns in the distri-
* buted matrix A, N_A >= 0.
* IMB_A (global) DESCA[ IMB_ ] The number of rows of the upper left
* block of the matrix A, IMB_A > 0.
* INB_A (global) DESCA[ INB_ ] The number of columns of the upper
* left block of the matrix A,
* INB_A > 0.
* MB_A (global) DESCA[ MB_ ] The blocking factor used to distri-
* bute the last M_A-IMB_A rows of A,
* MB_A > 0.
* NB_A (global) DESCA[ NB_ ] The blocking factor used to distri-
* bute the last N_A-INB_A columns of
* A, NB_A > 0.
* RSRC_A (global) DESCA[ RSRC_ ] The process row over which the first
* row of the matrix A is distributed,
* NPROW > RSRC_A >= 0.
* CSRC_A (global) DESCA[ CSRC_ ] The process column over which the
* first column of A is distributed.
* NPCOL > CSRC_A >= 0.
* LLD_A (local) DESCA[ LLD_ ] The leading dimension of the local
* array storing the local blocks of
* the distributed matrix A,
* IF( Lc( 1, N_A ) > 0 )
* LLD_A >= MAX( 1, Lr( 1, M_A ) )
* ELSE
* LLD_A >= 1.
*
* Let K be the number of rows of a matrix A starting at the global in-
* dex IA,i.e, A( IA:IA+K-1, : ). Lr( IA, K ) denotes the number of rows
* that the process of row coordinate MYROW ( 0 <= MYROW < NPROW ) would
* receive if these K rows were distributed over NPROW processes. If K
* is the number of columns of a matrix A starting at the global index
* JA, i.e, A( :, JA:JA+K-1, : ), Lc( JA, K ) denotes the number of co-
* lumns that the process MYCOL ( 0 <= MYCOL < NPCOL ) would receive if
* these K columns were distributed over NPCOL processes.
*
* The values of Lr() and Lc() may be determined via a call to the func-
* tion PB_Cnumroc:
* Lr( IA, K ) = PB_Cnumroc( K, IA, IMB_A, MB_A, MYROW, RSRC_A, NPROW )
* Lc( JA, K ) = PB_Cnumroc( K, JA, INB_A, NB_A, MYCOL, CSRC_A, NPCOL )
*
* Arguments
* =========
*
* N (global input) INTEGER.
* On entry, N specifies the length of the subvectors to be
* added. N must be at least zero.
*
* ALPHA (global input) COMPLEX
* On entry, ALPHA specifies the scalar alpha. When ALPHA is
* supplied as zero then the local entries of the array X cor-
* responding to the entries of the subvector sub( X ) need not
* be set on input.
*
* X (local input) COMPLEX array
* On entry, X is an array of dimension (LLD_X, Kx), where LLD_X
* is at least MAX( 1, Lr( 1, IX ) ) when INCX = M_X and
* MAX( 1, Lr( 1, IX+N-1 ) ) otherwise, and, Kx is at least
* Lc( 1, JX+N-1 ) when INCX = M_X and Lc( 1, JX ) otherwise.
* Before entry, this array contains the local entries of the
* matrix X.
*
* IX (global input) INTEGER
* On entry, IX specifies X's global row index, which points to
* the beginning of the submatrix sub( X ).
*
* JX (global input) INTEGER
* On entry, JX specifies X's global column index, which points
* to the beginning of the submatrix sub( X ).
*
* DESCX (global and local input) INTEGER array
* On entry, DESCX is an integer array of dimension DLEN_. This
* is the array descriptor for the matrix X.
*
* INCX (global input) INTEGER
* On entry, INCX specifies the global increment for the
* elements of X. Only two values of INCX are supported in
* this version, namely 1 and M_X. INCX must not be zero.
*
* Y (local input/local output) COMPLEX array
* On entry, Y is an array of dimension (LLD_Y, Ky), where LLD_Y
* is at least MAX( 1, Lr( 1, IY ) ) when INCY = M_Y and
* MAX( 1, Lr( 1, IY+N-1 ) ) otherwise, and, Ky is at least
* Lc( 1, JY+N-1 ) when INCY = M_Y and Lc( 1, JY ) otherwise.
* Before entry, this array contains the local entries of the
* matrix Y. On exit, sub( Y ) is overwritten with the updated
* subvector.
*
* IY (global input) INTEGER
* On entry, IY specifies Y's global row index, which points to
* the beginning of the submatrix sub( Y ).
*
* JY (global input) INTEGER
* On entry, JY specifies Y's global column index, which points
* to the beginning of the submatrix sub( Y ).
*
* DESCY (global and local input) INTEGER array
* On entry, DESCY is an integer array of dimension DLEN_. This
* is the array descriptor for the matrix Y.
*
* INCY (global input) INTEGER
* On entry, INCY specifies the global increment for the
* elements of Y. Only two values of INCY are supported in
* this version, namely 1 and M_Y. INCY must not be zero.
*
* -- Written on April 1, 1998 by
* Antoine Petitet, University of Tennessee, Knoxville 37996, USA.
*
* ---------------------------------------------------------------------
*/
/*
* .. Local Scalars ..
*/
int Xi, Xj, Yi, Yj, ctxt, info, mycol, myrow, npcol, nprow;
PBTYP_T * type;
/*
* .. Local Arrays ..
*/
int Xd[DLEN_], Yd[DLEN_];
/* ..
* .. Executable Statements ..
*
*/
PB_CargFtoC( *IX, *JX, DESCX, &Xi, &Xj, Xd );
PB_CargFtoC( *IY, *JY, DESCY, &Yi, &Yj, Yd );
#ifndef NO_ARGCHK
/*
* Test the input parameters
*/
Cblacs_gridinfo( ( ctxt = Xd[CTXT_] ), &nprow, &npcol, &myrow, &mycol );
if( !( info = ( ( nprow == -1 ) ? -( 601 + CTXT_ ) : 0 ) ) )
{
PB_Cchkvec( ctxt, "PCAXPY", "X", *N, 1, Xi, Xj, Xd, *INCX, 6, &info );
PB_Cchkvec( ctxt, "PCAXPY", "Y", *N, 1, Yi, Yj, Yd, *INCY, 11, &info );
}
if( info ) { PB_Cabort( ctxt, "PCAXPY", info ); return; }
#endif
/*
* Quick return if possible
*/
if( ( *N == 0 ) ||
( ( ALPHA[REAL_PART] == ZERO ) && ( ALPHA[IMAG_PART] == ZERO ) ) )
return;
/*
* Get type structure
*/
type = PB_Cctypeset();
/*
* Start the operations
*/
if( *INCX == Xd[M_] )
{
PB_Cpaxpby( type, NOCONJG, 1, *N, ((char *) ALPHA), ((char *) X),
Xi, Xj, Xd, ROW, type->one, ((char *) Y), Yi, Yj, Yd,
( *INCY == Yd[M_] ? ROW : COLUMN ) );
}
else
{
PB_Cpaxpby( type, NOCONJG, *N, 1, ((char *) ALPHA), ((char *) X),
Xi, Xj, Xd, COLUMN, type->one, ((char *) Y), Yi, Yj, Yd,
( *INCY == Yd[M_] ? ROW : COLUMN ) );
}
/*
* End of PCAXPY
*/
}
