..
     .. Array Arguments ..
     ..
  Purpose
  =======
  PSRSCL multiplies an N-element real distributed vector sub( X ) by
  the real scalar 1/a. This is done without overflow or underflow as
  long as the final result sub( X )/a does not overflow or underflow.
  where sub( X ) denotes X(IX:IX+N-1,JX:JX), if INCX = 1,
                         X(IX:IX,JX:JX+N-1), if INCX = M_X.
  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
  --------------- -------------- --------------------------------------
  DT_A   (global) descA[ DT_ ]   The descriptor type.  In this case,
                                 DT_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 distribu-
                                 te the rows of the array.
  NB_A   (global) descA[ NB_ ]   The blocking factor used to distribu-
                                 te 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
  Because vectors may be seen as particular matrices, a distributed
  vector is considered to be a distributed matrix.
  Arguments
  =========
  N       (global input) pointer to INTEGER
          The number of components of the distributed vector sub( X ).
          N >= 0.
  SA      (global input) REAL
          The scalar a which is used to divide each component of
          sub( X ).  SA must be >= 0, or the subroutine will divide by
          zero.
  SX      (local input/local output) REAL array
          containing the local pieces of a distributed matrix of
          dimension of at least
              ( (JX-1)*M_X + IX + ( N - 1 )*abs( INCX ) )
          This array contains the entries of the distributed vector
          sub( X ).
  IX      (global input) pointer to INTEGER
          The global row index of the submatrix of the distributed
          matrix X to operate on.
  JX      (global input) pointer to INTEGER
          The global column index of the submatrix of the distributed
          matrix X to operate on.
  DESCX   (global and local input) INTEGER array of dimension 8.
          The array descriptor of the distributed matrix X.
  INCX    (global input) pointer to INTEGER
          The global increment for the elements of X. Only two values
          of INCX are supported in this version, namely 1 and M_X.
 =====================================================================
     .. Parameters ..