NAME

       PSLASCL  -  multiplie  the M-by-N real distributed matrix sub( A ) denoting A(IA:IA+M-1,JA:JA+N-1) by the
       real scalar CTO/CFROM

SYNOPSIS

       SUBROUTINE PSLASCL( TYPE, CFROM, CTO, M, N, A, IA, JA, DESCA, INFO )

           CHARACTER       TYPE

           INTEGER         IA, INFO, JA, M, N

           REAL            CFROM, CTO

           INTEGER         DESCA( * )

           REAL            A( * )

PURPOSE

       PSLASCL multiplies the M-by-N real distributed matrix sub( A )  denoting  A(IA:IA+M-1,JA:JA+N-1)  by  the
       real  scalar  CTO/CFROM.   This is done without over/underflow as long as the final result CTO * A(I,J) /
       CFROM does not over/underflow. TYPE specifies that  sub(  A  )  may  be  full,  upper  triangular,  lower
       triangular or upper Hessenberg.

       Notes
       =====

       Each  global  data  object  is  described  by  an  associated description vector.  This vector stores the
       information required to establish the mapping between an object element and its corresponding process and
       memory location.

       Let A be a generic term for any 2D block  cyclicly  distributed  array.   Such  a  global  array  has  an
       associated  description  vector  DESCA.  In the following comments, the character _ should be read as "of
       the global array".

       NOTATION        STORED IN      EXPLANATION
       --------------- -------------- -------------------------------------- DTYPE_A(global) DESCA( DTYPE_  )The
       descriptor type.  In this case,
                                      DTYPE_A = 1.
       CTXT_A (global) DESCA( CTXT_ ) The BLACS context handle, indicating
                                      the BLACS process grid A is distribu-
                                      ted over. The context itself is glo-
                                      bal, but the handle (the integer
                                      value) may vary.
       M_A    (global) DESCA( M_ )    The number of rows in the global
                                      array A.
       N_A    (global) DESCA( N_ )    The number of columns in the global
                                      array A.
       MB_A   (global) DESCA( MB_ )   The blocking factor used to distribute
                                      the rows of the array.
       NB_A   (global) DESCA( NB_ )   The blocking factor used to distribute
                                      the columns of the array.
       RSRC_A (global) DESCA( RSRC_ ) The process row over which the first
                                      row  of  the  array  A is distributed.  CSRC_A (global) DESCA( CSRC_ ) The
       process column over which the
                                      first column of the array A is
                                      distributed.
       LLD_A  (local)  DESCA( LLD_ )  The leading dimension of the local
                                      array.  LLD_A >= MAX(1,LOCr(M_A)).

       Let K be the number of rows or columns of a distributed matrix, and assume  that  its  process  grid  has
       dimension p x q.
       LOCr( K ) denotes the number of elements of K that a process would receive if K were distributed over the
       p processes of its process column.
       Similarly,  LOCc(  K  )  denotes  the  number  of  elements  of  K that a process would receive if K were
       distributed over the q processes of its process row.
       The values of LOCr() and LOCc() may be determined via a call to the ScaLAPACK tool function, NUMROC:
               LOCr( M ) = NUMROC( M, MB_A, MYROW, RSRC_A, NPROW ),
               LOCc( N ) = NUMROC( N, NB_A, MYCOL, CSRC_A, NPCOL ).  An upper bound for these quantities may  be
       computed by:
               LOCr( M ) <= ceil( ceil(M/MB_A)/NPROW )*MB_A
               LOCc( N ) <= ceil( ceil(N/NB_A)/NPCOL )*NB_A

ARGUMENTS

       TYPE    (global input) CHARACTER
               TYPE  indices  the  storage  type  of  the  input distributed matrix.  = 'G':  sub( A ) is a full
               matrix,
               = 'L':  sub( A ) is a lower triangular matrix,
               = 'U':  sub( A ) is an upper triangular matrix,
               = 'H':  sub( A ) is an upper Hessenberg matrix.

       CFROM   (global input) REAL
               CTO     (global input) REAL The distributed matrix sub( A ) is multiplied by  CTO/CFROM.   A(I,J)
               is  computed  without  over/underflow if the final result CTO * A(I,J) / CFROM can be represented
               without over/underflow.  CFROM must be nonzero.

       M       (global input) INTEGER
               The number of rows to be operated on i.e the number of rows of the distributed submatrix  sub(  A
               ). M >= 0.

       N       (global input) INTEGER
               The  number  of  columns to be operated on i.e the number of columns of the distributed submatrix
               sub( A ). N >= 0.

       A       (local input/local output) REAL pointer into the
               local memory to an array of dimension (LLD_A,LOCc(JA+N-1)).  This array contains the local pieces
               of the distributed matrix sub( A ). On  exit,  this  array  contains  the  local  pieces  of  the
               distributed matrix multiplied by CTO/CFROM.

       IA      (global input) INTEGER
               The row index in the global array A indicating the first row of sub( A ).

       JA      (global input) INTEGER
               The column index in the global array A indicating the first column of sub( A ).

       DESCA   (global and local input) INTEGER array of dimension DLEN_.
               The array descriptor for the distributed matrix A.

       INFO    (local output) INTEGER
               = 0:  successful exit
               <  0:   If  the  i-th  argument  is  an  array  and the j-entry had an illegal value, then INFO =
               -(i*100+j), if the i-th argument is a scalar and had an illegal value, then INFO = -i.

LAPACK version 1.5                                 12 May 1997                                        PSLASCL(l)