zupmtr(3S)

NAME
     ZUPMTR - overwrite the general complex M-by-N matrix C with  SIDE = 'L'
     SIDE = 'R' TRANS = 'N'

SYNOPSIS
     SUBROUTINE ZUPMTR( SIDE, UPLO, TRANS, M, N, AP, TAU, C, LDC, WORK, INFO )

         CHARACTER      SIDE, TRANS, UPLO

         INTEGER        INFO, LDC, M, N

         COMPLEX*16     AP( * ), C( LDC, * ), TAU( * ), WORK( * )

IMPLEMENTATION
     These routines are part of the SCSL Scientific Library and can be loaded
     using either the -lscs or the -lscs_mp option.  The -lscs_mp option
     directs the linker to use the multi-processor version of the library.

     When linking to SCSL with -lscs or -lscs_mp, the default integer size is
     4 bytes (32 bits). Another version of SCSL is available in which integers
     are 8 bytes (64 bits).  This version allows the user access to larger
     memory sizes and helps when porting legacy Cray codes.  It can be loaded
     by using the -lscs_i8 option or the -lscs_i8_mp option. A program may use
     only one of the two versions; 4-byte integer and 8-byte integer library
     calls cannot be mixed.

PURPOSE
     ZUPMTR overwrites the general complex M-by-N matrix C with SIDE = 'L'
     SIDE = 'R' TRANS = 'N': Q * C C * Q TRANS = 'C':      Q**H * C       C *
     Q**H

     where Q is a complex unitary matrix of order nq, with nq = m if SIDE =
     'L' and nq = n if SIDE = 'R'. Q is defined as the product of nq-1
     elementary reflectors, as returned by ZHPTRD using packed storage:

     if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);

     if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).


ARGUMENTS
     SIDE    (input) CHARACTER*1
             = 'L': apply Q or Q**H from the Left;
             = 'R': apply Q or Q**H from the Right.

     UPLO    (input) CHARACTER*1
             = 'U': Upper triangular packed storage used in previous call to
             ZHPTRD; = 'L': Lower triangular packed storage used in previous
             call to ZHPTRD.
     TRANS   (input) CHARACTER*1
             = 'N':  No transpose, apply Q;
             = 'C':  Conjugate transpose, apply Q**H.

     M       (input) INTEGER
             The number of rows of the matrix C. M >= 0.

     N       (input) INTEGER
             The number of columns of the matrix C. N >= 0.

     AP      (input) COMPLEX*16 array, dimension
             (M*(M+1)/2) if SIDE = 'L' (N*(N+1)/2) if SIDE = 'R' The vectors
             which define the elementary reflectors, as returned by ZHPTRD.
             AP is modified by the routine but restored on exit.

     TAU     (input) COMPLEX*16 array, dimension (M-1) if SIDE = 'L'
             or (N-1) if SIDE = 'R' TAU(i) must contain the scalar factor of
             the elementary reflector H(i), as returned by ZHPTRD.

     C       (input/output) COMPLEX*16 array, dimension (LDC,N)
             On entry, the M-by-N matrix C.  On exit, C is overwritten by Q*C
             or Q**H*C or C*Q**H or C*Q.

     LDC     (input) INTEGER
             The leading dimension of the array C. LDC >= max(1,M).

     WORK    (workspace) COMPLEX*16 array, dimension
             (N) if SIDE = 'L' (M) if SIDE = 'R'

     INFO    (output) INTEGER
             = 0:  successful exit
             < 0:  if INFO = -i, the i-th argument had an illegal value

SEE ALSO
     INTRO_LAPACK(3S), INTRO_SCSL(3S)

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