dopmtr.f(3)

NAME
dopmtr.f

SYNOPSIS

  Functions/Subroutines
subroutine dopmtr (SIDE, UPLO, TRANS, M, N, AP, TAU, C, LDC, WORK, INFO)
DOPMTR

Function/Subroutine Documentation

  subroutine dopmtr (character SIDE, character UPLO, character TRANS, integer M, integer N, double precision, dimension( * ) AP, double precision, dimension( * ) TAU, double precision, dimension( ldc, * ) C, integer LDC, double precision, dimension( * ) WORK, integer INFO)

Purpose:

     DOPMTR overwrites the general real M-by-N matrix C with
                     SIDE = 'L'     SIDE = 'R'
     TRANS = 'N':      Q * C          C * Q
     TRANS = 'T':      Q**T * C       C * Q**T
     where Q is a real orthogonal 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 DSPTRD 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).

Parameters
    SIDE

              SIDE is CHARACTER*1
              = 'L': apply Q or Q**T from the Left;
              = 'R': apply Q or Q**T from the Right.

    UPLO

              UPLO is CHARACTER*1
              = 'U': Upper triangular packed storage used in previous
                     call to DSPTRD;
              = 'L': Lower triangular packed storage used in previous
                     call to DSPTRD.

    TRANS

              TRANS is CHARACTER*1
              = 'N':  No transpose, apply Q;
              = 'T':  Transpose, apply Q**T.

    M

              M is INTEGER
              The number of rows of the matrix C. M >= 0.

    N

              N is INTEGER
              The number of columns of the matrix C. N >= 0.

    AP

              AP is DOUBLE PRECISION 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 DSPTRD.  AP is modified by the routine but
              restored on exit.

    TAU

              TAU is DOUBLE PRECISION 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 DSPTRD.

    C

              C is DOUBLE PRECISION array, dimension (LDC,N)
              On entry, the M-by-N matrix C.
              On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.

    LDC

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

    WORK

              WORK is DOUBLE PRECISION array, dimension
                                       (N) if SIDE = 'L'
                                       (M) if SIDE = 'R'

    INFO

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

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 148 of file dopmtr.f.

Author

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