pb_descset2()

subroutine pb_descset2	(	integer, dimension( * )	desc,
		integer	m,
		integer	n,
		integer	imb,
		integer	inb,
		integer	mb,
		integer	nb,
		integer	rsrc,
		integer	csrc,
		integer	ctxt,
		integer	lld
	)

Definition at line 3170 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
*
*     .. Scalar Arguments ..
      INTEGER            CSRC, CTXT, IMB, INB, LLD, M, MB, N, NB, RSRC
*     ..
*     .. Array Arguments ..
      INTEGER            DESC( * )
*     ..
*
*  Purpose
*  =======
*
*  PB_DESCSET2 uses  its  10  input  arguments  M,  N, IMB, INB, MB, NB,
*  RSRC,  CSRC,  CTXT  and LLD to initialize a descriptor vector of type
*  BLOCK_CYCLIC_2D_INB.
*
*  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 )
*
*  Arguments
*  =========
*
*  DESC    (global and local output) INTEGER array
*          On entry, DESC is an array of  dimension  DLEN_.  DESC is the
*          array descriptor to be set.
*
*  M       (global input) INTEGER
*          On entry,  M  specifies  the  number  of  rows of the matrix.
*          M must be at least zero.
*
*  N       (global input) INTEGER
*          On entry,  N  specifies  the number of columns of the matrix.
*          N must be at least zero.
*
*  IMB     (global input) INTEGER
*          On entry,  IMB  specifies  the row size of the first block of
*          the global matrix distribution. IMB must be at least one.
*
*  INB     (global input) INTEGER
*          On entry,  INB  specifies  the column size of the first block
*          of the global matrix distribution. INB must be at least one.
*
*  MB      (global input) INTEGER
*          On entry,  MB  specifies  the  row size of the blocks used to
*          partition the matrix. MB must be at least one.
*
*  NB      (global input) INTEGER
*          On entry, NB  specifies the column size of the blocks used to
*          partition the matrix. NB must be at least one.
*
*  RSRC    (global input) INTEGER
*          On entry,  RSRC  specifies  the row coordinate of the process
*          that possesses the first row of the matrix.  When  RSRC = -1,
*          the data is not  distributed but replicated,  otherwise  RSRC
*          must be at least zero and strictly less than NPROW.
*
*  CSRC    (global input) INTEGER
*          On entry,  CSRC  specifies  the column coordinate of the pro-
*          cess  that  possesses  the  first column of the matrix.  When
*          CSRC = -1, the data is not distributed but replicated, other-
*          wise CSRC must be at least zero and strictly less than NPCOL.
*
*  CTXT    (local input) INTEGER
*          On entry, CTXT specifies the BLACS context handle, indicating
*          the global  communication  context.  The value of the context
*          itself is local.
*
*  LLD     (local input)  INTEGER
*          On entry, LLD  specifies  the  leading dimension of the local
*          array storing the local entries of the matrix. LLD must be at
*          least MAX( 1, Lr(1,M) ).
*
*  -- Written on April 1, 1998 by
*     Antoine Petitet, University  of  Tennessee, Knoxville 37996, USA.
*
*  =====================================================================
*
*     .. Parameters ..
      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 )
*     ..
*     .. Executable Statements ..
*
      desc( dtype_ ) = block_cyclic_2d_inb
      desc( ctxt_  ) = ctxt
      desc( m_     ) = m
      desc( n_     ) = n
      desc( imb_   ) = imb
      desc( inb_   ) = inb
      desc( mb_    ) = mb
      desc( nb_    ) = nb
      desc( rsrc_  ) = rsrc
      desc( csrc_  ) = csrc
      desc( lld_   ) = lld
*
      RETURN
*
*     End of PB_DESCSET2
*

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