PCLACGV(3)    ScaLAPACK routine of NEC Numeric Library Collection   PCLACGV(3)



NAME
       PCLACGV  - conjugate a complex vector of length N, sub( X ), where sub(
       X ) denotes X(IX,JX:JX+N-1) if INCX = DESCX( M_ )  and  X(IX:IX+N-1,JX)
       if  INCX = 1, and  Notes =====  Each global data object is described by
       an associated description vector

SYNOPSIS
       SUBROUTINE PCLACGV( N, X, IX, JX, DESCX, INCX )

           INTEGER         INCX, IX, JX, N

           INTEGER         DESCX( * )

           COMPLEX         X( * )

PURPOSE
       PCLACGV conjugates a complex vector of length N, sub( X ), where sub( X
       )  denotes X(IX,JX:JX+N-1) if INCX = DESCX( M_ ) and X(IX:IX+N-1,JX) if
       INCX = 1, and 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 col-
       umn.
       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.


ARGUMENTS
       N       (global input) INTEGER
               The length of the distributed vector sub( X ).

       X       (local input/local output) COMPLEX pointer into the
               local  memory to an array of dimension (LLD_X,*).  On entry the
               vector to be conjugated x( i )  =  X(IX+(JX-1)*M_X  +(i-1)*INCX
               ), 1 <= i <= N.  On exit the conjugated vector.

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

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

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

       INCX    (global input) INTEGER
               The  global increment for the elements of X. Only two values of
               INCX are supported in this version, namely  1  and  M_X.   INCX
               must not be zero.



ScaLAPACK routine               31 October 2017                     PCLACGV(3)