PB_Cplacnjg.c

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/* ---------------------------------------------------------------------
*
*  -- PBLAS auxiliary routine (version 2.0) --
*     University of Tennessee, Knoxville, Oak Ridge National Laboratory,
*     and University of California, Berkeley.
*     April 1, 1998
*
*  ---------------------------------------------------------------------
*/
/*
*  Include files
*/
#include "../pblas.h"
#include "../PBpblas.h"
#include "../PBtools.h"
#include "../PBblacs.h"
#include "../PBblas.h"
 
#ifdef __STDC__
void PB_Cplacnjg( PBTYP_T * TYPE, Int M, Int N, char * ALPHA, char * A,
                  Int IA, Int JA, Int * DESCA )
#else
void PB_Cplacnjg( TYPE, M, N, ALPHA, A, IA, JA, DESCA )
/*
*  .. Scalar Arguments ..
*/
   Int            IA, JA, M, N;
   char           * ALPHA;
   PBTYP_T        * TYPE;
/*
*  .. Array Arguments ..
*/
   Int            * DESCA;
   char           * A;
#endif
{
/*
*  Purpose
*  =======
*
*  PB_Cplacnjg conjugates and scales by alpha and  an  m by n  submatrix
*  sub( A ) denoting A(IA:IA+M-1,JA:JA+N-1).
*
*  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
*  =========
*
*  TYPE    (local input) pointer to a PBTYP_T structure
*          On entry,  TYPE  is a pointer to a structure of type PBTYP_T,
*          that contains type information (See pblas.h).
*
*  M       (global input) INTEGER
*          On entry,  M  specifies the number of rows of  the  submatrix
*          sub( A ). M  must be at least zero.
*
*  N       (global input) INTEGER
*          On entry, N  specifies the number of columns of the submatrix
*          sub( A ). N must be at least zero.
*
*  ALPHA   (global input) pointer to CHAR
*          On entry,  ALPHA  specifies the scalar alpha, i.e., the cons-
*          tant with which the matrix elements are to be scaled.
*
*  A       (local input/local output) pointer to CHAR
*          On entry, A is an array of dimension (LLD_A, Ka), where Ka is
*          at least Lc( 1, JA+N-1 ).  Before  entry, this array contains
*          the local entries of the matrix A to be scaled.  On exit, the
*          local  entries  of this array corresponding to the to the en-
*          tries of the submatrix sub( A ) are  overwritten by the local
*          entries of the m by n conjugated and scaled submatrix.
*
*  IA      (global input) INTEGER
*          On entry, IA  specifies A's global row index, which points to
*          the beginning of the submatrix sub( A ).
*
*  JA      (global input) INTEGER
*          On entry, JA  specifies A's global column index, which points
*          to the beginning of the submatrix sub( A ).
*
*  DESCA   (global and local input) INTEGER array
*          On entry, DESCA  is an integer array of dimension DLEN_. This
*          is the array descriptor for the matrix A.
*
*  -- Written on April 1, 1998 by
*     Antoine Petitet, University of Tennessee, Knoxville 37996, USA.
*
*  ---------------------------------------------------------------------
*/
/*
*  .. Local Scalars ..
*/
   Int            Acol, Arow, Aii, Aimb1, Ainb1, Ajj, Ald, Amb, Amp, Anb, Anq,
                  izero=0, mycol, myrow, npcol, nprow;
/*
*  .. Local Arrays ..
*/
   Int            Ad0[DLEN_];
/* ..
*  .. Executable Statements ..
*
*/
/*
*  Quick return if possible
*/
   if( ( M <= 0 ) || ( N <= 0 ) ) return;
/*
*  Retrieve process grid information
*/
   Cblacs_gridinfo( DESCA[CTXT_], &nprow, &npcol, &myrow, &mycol );
/*
*  Compute descriptor Ad0 for sub( A )
*/
   PB_Cdescribe( M, N, IA, JA, DESCA, nprow, npcol, myrow, mycol, &Aii, &Ajj,
                 &Ald, &Aimb1, &Ainb1, &Amb, &Anb, &Arow, &Acol, Ad0 );
/*
*  Quick return if I don't own any of sub( A ).
*/
   Amp  = PB_Cnumroc( M, 0, Aimb1, Amb, myrow, Arow, nprow );
   Anq  = PB_Cnumroc( N, 0, Ainb1, Anb, mycol, Acol, npcol );
   if( ( Amp <= 0 ) || ( Anq <= 0 ) ) return;
/*
*  Conjugate and scale local data
*/
   TYPE->Ftzcnjg( C2F_CHAR( ALL ), &Amp, &Anq, &izero, ALPHA,
                  Mptr( A, Aii, Ajj, Ald, TYPE->size ), &Ald );
/*
*  End of PB_Cplacnjg
*/
}