dormhr.f(3)

NAME
dormhr.f -

SYNOPSIS

  Functions/Subroutines
subroutine dormhr (SIDE, TRANS, M, N, ILO, IHI, A, LDA, TAU, C, LDC, WORK, LWORK, INFO)
DORMHR

Function/Subroutine Documentation

  subroutine dormhr (characterSIDE, characterTRANS, integerM, integerN, integerILO, integerIHI, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU, double precision, dimension( ldc, * )C, integerLDC, double precision, dimension( * )WORK, integerLWORK, integerINFO)

DORMHR

Purpose:

     DORMHR 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
     IHI-ILO elementary reflectors, as returned by DGEHRD:
     Q = H(ilo) H(ilo+1) . . . H(ihi-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.

    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.

    ILO

              ILO is INTEGER

    IHI

              IHI is INTEGER
              ILO and IHI must have the same values as in the previous call
              of DGEHRD. Q is equal to the unit matrix except in the
              submatrix Q(ilo+1:ihi,ilo+1:ihi).
              If SIDE = 'L', then 1 <= ILO <= IHI <= M, if M > 0, and
              ILO = 1 and IHI = 0, if M = 0;
              if SIDE = 'R', then 1 <= ILO <= IHI <= N, if N > 0, and
              ILO = 1 and IHI = 0, if N = 0.

    A

              A is DOUBLE PRECISION array, dimension
                                   (LDA,M) if SIDE = 'L'
                                   (LDA,N) if SIDE = 'R'
              The vectors which define the elementary reflectors, as
              returned by DGEHRD.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.
              LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'.

    TAU

              TAU is DOUBLE PRECISION array, dimension
                                   (M-1) if SIDE = 'L'
                                   (N-1) if SIDE = 'R'
              TAU(i) must contain the scalar factor of the elementary
              reflector H(i), as returned by DGEHRD.

    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 (MAX(1,LWORK))
              On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

    LWORK

              LWORK is INTEGER
              The dimension of the array WORK.
              If SIDE = 'L', LWORK >= max(1,N);
              if SIDE = 'R', LWORK >= max(1,M).
              For optimum performance LWORK >= N*NB if SIDE = 'L', and
              LWORK >= M*NB if SIDE = 'R', where NB is the optimal
              blocksize.
              If LWORK = -1, then a workspace query is assumed; the routine
              only calculates the optimal size of the WORK array, returns
              this value as the first entry of the WORK array, and no error
              message related to LWORK is issued by XERBLA.

    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.

Date:
    November 2011

Definition at line 178 of file dormhr.f.

Author

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