..
     .. Array Arguments ..
     ..
  Purpose
  =======
  PSCSUM1 returns the sum of absolute values of a complex
  distributed vector sub( X ) in ASUM,
  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.
  Based on PSCASUM from the Level 1 PBLAS. The change is
  to use the 'genuine' absolute value.
  The serial version of this routine was originally contributed by
  Nick Higham for use with CLACON.
  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
  Because vectors may be viewed as a subclass of matrices, a
  distributed vector is considered to be a distributed matrix.
  When the result of a vector-oriented PBLAS call is a scalar, it will
  be made available only within the scope which owns the vector(s)
  being operated on.  Let X be a generic term for the input vector(s).
  Then, the processes which receive the answer will be (note that if
  an operation involves more than one vector, the processes which re-
  ceive the result will be the union of the following calculation for
  each vector):
  If N = 1, M_X = 1 and INCX = 1, then one can't determine if a process
  row or process column owns the vector operand, therefore only the
  process of coordinate {RSRC_X, CSRC_X} receives the result;
  If INCX = M_X, then sub( X ) is a vector distributed over a process
  row. Each process part of this row receives the result;
  If INCX = 1, then sub( X ) is a vector distributed over a process
  column. Each process part of this column receives the result;
  Parameters
  ==========
  N       (global input) pointer to INTEGER
          The number of components of the distributed vector sub( X ).
          N >= 0.
  ASUM    (local output) pointer to REAL
          The sum of absolute values of the distributed vector sub( X )
          only in its scope.
  X       (local input) COMPLEX 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 ..