pb_desctrans()

subroutine pb_desctrans	(	integer, dimension( * )	descin,
		integer, dimension( * )	descout
	)

Definition at line 2963 of file pblastst.f.

*
*  -- PBLAS test routine (version 2.0) --
*     University of Tennessee, Knoxville, Oak Ridge National Laboratory,
*     and University of California, Berkeley.
*     April 1, 1998
*
*     .. Array Arguments ..
      INTEGER            DESCIN( * ), DESCOUT( * )
*     ..
*
*  Purpose
*  =======
*
*  PB_DESCTRANS  converts  a  descriptor  DESCIN of type BLOCK_CYCLIC_2D
*  or   BLOCK_CYCLIC_INB_2D   into   a   descriptor   DESCOUT   of  type
*  BLOCK_CYCLIC_INB_2D.
*
*  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 DESCA:
*
*  NOTATION         STORED IN        EXPLANATION
*  ---------------- ---------------  -----------------------------------
*  DTYPE_A (global) DESCA( DTYPE1_ ) The descriptor type.
*  CTXT_A  (global) DESCA( CTXT1_  ) 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( M1_     ) The  number  of rows in the distri-
*                                    buted matrix A, M_A >= 0.
*  N_A     (global) DESCA( N1_     ) The  number  of columns in the dis-
*                                    tributed matrix A, N_A >= 0.
*  MB_A    (global) DESCA( MB1_    ) The blocking factor used to distri-
*                                    bute the rows of A, MB_A > 0.
*  NB_A    (global) DESCA( NB1_    ) The blocking factor used to distri-
*                                    bute the columns of A, NB_A > 0.
*  RSRC_A  (global) DESCA( RSRC1_  ) The  process  row  over  which  the
*                                    first row of the matrix  A  is dis-
*                                    tributed, NPROW > RSRC_A >= 0.
*  CSRC_A  (global) DESCA( CSRC1_  ) The process column  over  which the
*                                    first column of  A  is distributed.
*                                    NPCOL > CSRC_A >= 0.
*  LLD_A   (local)  DESCA( LLD1_   ) 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_NUMROC:
*  Lr( IA, K ) = PB_NUMROC( K, IA, MB_A, MB_A, MYROW, RSRC_A, NPROW )
*  Lc( JA, K ) = PB_NUMROC( K, JA, NB_A, NB_A, MYCOL, CSRC_A, NPCOL )
*
*  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 DESCA:
*
*  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_NUMROC:
*  Lr( IA, K ) = PB_NUMROC( K, IA, IMB_A, MB_A, MYROW, RSRC_A, NPROW )
*  Lc( JA, K ) = PB_NUMROC( K, JA, INB_A, NB_A, MYCOL, CSRC_A, NPCOL )
*
*  Arguments
*  =========
*
*  DESCIN  (global and local input) INTEGER array
*          On entry, DESCIN  is an array of dimension DLEN1_ or DLEN_ as
*          specified by its first entry DESCIN( DTYPE_ ).  DESCIN is the
*          source  array  descriptor of type BLOCK_CYCLIC_2D  or of type
*          BLOCK_CYCLIC_2D_INB.
*
*  DESCOUT (global and local output) INTEGER array
*          On entry, DESCOUT is an array of dimension DLEN_.  DESCOUT is
*          the target array descriptor of type BLOCK_CYCLIC_2D_INB.
*
*  -- Written on April 1, 1998 by
*     R. Clint Whaley, University of Tennessee, Knoxville 37996, USA.
*
*  =====================================================================
*
*     .. Parameters ..
      INTEGER            BLOCK_CYCLIC_2D, CSRC1_, CTXT1_, DLEN1_,
     $                   DTYPE1_, LLD1_, M1_, MB1_, N1_, NB1_, RSRC1_
      parameter( block_cyclic_2d = 1, dlen1_ = 9, dtype1_ = 1,
     $                   ctxt1_ = 2, m1_ = 3, n1_ = 4, mb1_ = 5,
     $                   nb1_ = 6, rsrc1_ = 7, csrc1_ = 8, lld1_ = 9 )
      INTEGER            BLOCK_CYCLIC_2D_INB, CSRC_, CTXT_, DLEN_,
     $                   DTYPE_, IMB_, INB_, LLD_, MB_, M_, NB_, N_,
     $                   RSRC_
      parameter( block_cyclic_2d_inb = 2, dlen_ = 11,
     $                   dtype_ = 1, ctxt_ = 2, m_ = 3, n_ = 4,
     $                   imb_ = 5, inb_ = 6, mb_ = 7, nb_ = 8,
     $                   rsrc_ = 9, csrc_ = 10, lld_ = 11 )
*     ..
*     .. Local Scalars ..
      INTEGER            I
*     ..
*     .. Executable Statements ..
*
      IF( descin( dtype_ ).EQ.block_cyclic_2d ) THEN
         descout( dtype_ ) = block_cyclic_2d_inb
         descout( ctxt_  ) = descin( ctxt1_ )
         descout( m_     ) = descin( m1_    )
         descout( n_     ) = descin( n1_    )
         descout( imb_   ) = descin( mb1_   )
         descout( inb_   ) = descin( nb1_   )
         descout( mb_    ) = descin( mb1_   )
         descout( nb_    ) = descin( nb1_   )
         descout( rsrc_  ) = descin( rsrc1_ )
         descout( csrc_  ) = descin( csrc1_ )
         descout( lld_   ) = descin( lld1_  )
      ELSE IF( descin( dtype_ ).EQ.block_cyclic_2d_inb ) THEN
         DO 10 i = 1, dlen_
            descout( i ) = descin( i )
   10    CONTINUE
      ELSE
         descout( dtype_ ) = descin( 1 )
         descout( ctxt_  ) = descin( 2 )
         descout( m_     ) = 0
         descout( n_     ) = 0
         descout( imb_   ) = 1
         descout( inb_   ) = 1
         descout( mb_    ) = 1
         descout( nb_    ) = 1
         descout( rsrc_  ) = 0
         descout( csrc_  ) = 0
         descout( lld_   ) = 1
      END IF
*
      RETURN
*
*     End of PB_DESCTRANS
*

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