NAME

       PDLASCL   -   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 PDLASCL( TYPE, CFROM, CTO, M, N, A, IA, JA, DESCA, INFO )

           CHARACTER       TYPE

           INTEGER         IA, INFO, JA, M, N

           DOUBLE          PRECISION CFROM, CTO

           INTEGER         DESCA( * )

           DOUBLE          PRECISION A( * )

PURPOSE

       PDLASCL  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) DOUBLE PRECISION
               CTO      (global  input)  DOUBLE  PRECISION  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) DOUBLE PRECISION 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.