pchkpbe()

subroutine pchkpbe	(	integer	ictxt,
		integer	nout,
		character*(*)	sname,
		integer	infot
	)

Definition at line 1083 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            ICTXT, INFOT, NOUT
      CHARACTER*(*)      SNAME
*     ..
*
*  Purpose
*  =======
*
*  PCHKPBE  tests  whether a PBLAS routine has detected an error when it
*  should.  This routine does a global operation to ensure all processes
*  have detected this error.  If  an  error  has  been detected an error
*  message is displayed.
*
*  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( 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
*  =========
*
*  ICTXT   (local input) INTEGER
*          On entry,  ICTXT  specifies the BLACS context handle, indica-
*          ting the global  context of the operation. The context itself
*          is global, but the value of ICTXT is local.
*
*  NOUT    (global input) INTEGER
*          On entry, NOUT specifies the unit number for the output file.
*          When NOUT is 6, output to screen,  when  NOUT is 0, output to
*          stderr. NOUT is only defined for process 0.
*
*  SNAME   (global input) CHARACTER*(*)
*          On entry, SNAME specifies the subroutine  name  calling  this
*          subprogram.
*
*  INFOT   (global input) INTEGER
*          On entry, INFOT specifies the position of the wrong argument.
*          If  the  PBLAS  error  handler is called, INFO will be set to
*          -INFOT.  This  routine  verifies if the error was reported by
*          all processes by doing a global sum, and assert the result to
*          be NPROW * NPCOL.
*
*  -- Written on April 1, 1998 by
*     Antoine Petitet, University  of  Tennessee, Knoxville 37996, USA.
*
*  =====================================================================
*
*     .. Local Scalars ..
      INTEGER            GERR, MYCOL, MYROW, NPCOL, NPROW
*     ..
*     .. External Subroutines ..
      EXTERNAL           blacs_gridinfo, igsum2d
*     ..
*     .. Common Blocks ..
      INTEGER            INFO, NBLOG
      COMMON             /infoc/info, nblog
*     ..
*     .. Executable Statements ..
*
      CALL blacs_gridinfo( ictxt, nprow, npcol, myrow, mycol )
*
      gerr = 0
      IF( info.NE.-infot )
     $   gerr = 1
*
      CALL igsum2d( ictxt, 'All', ' ', 1, 1, gerr, 1, -1, 0 )
*
      IF( myrow.EQ.0 .AND. mycol.EQ.0 ) THEN
         IF( gerr.EQ.( nprow * npcol ) ) THEN
            WRITE( nout, fmt = 9999 ) sname, info, -infot
         END IF
      END IF
*
 9999 FORMAT( 1x, a7, ': *** ERROR *** ERROR CODE RETURNED = ', i6,
     $        ' SHOULD HAVE BEEN ', i6 )
*
      RETURN
*
*     End of PCHKPBE
*

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