Provided by: liblapack-doc_3.3.1-1_all bug

NAME

       LAPACK-3 - generates a real orthogonal matrix Q which is defined as the product of IHI-ILO
       elementary reflectors of order N, as returned by DGEHRD

SYNOPSIS

       SUBROUTINE DORGHR( N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO )

           INTEGER        IHI, ILO, INFO, LDA, LWORK, N

           DOUBLE         PRECISION A( LDA, * ), TAU( * ), WORK( * )

PURPOSE

       DORGHR generates a real orthogonal matrix Q which is defined as  the  product  of  IHI-ILO
       elementary reflectors of order N, as returned by DGEHRD:
        Q = H(ilo) H(ilo+1) . . . H(ihi-1).

ARGUMENTS

        N       (input) INTEGER
                The order of the matrix Q. N >= 0.

        ILO     (input) INTEGER
                IHI     (input) 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).
                1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.

        A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
                On entry, the vectors which define the elementary reflectors,
                as returned by DGEHRD.
                On exit, the N-by-N orthogonal matrix Q.

        LDA     (input) INTEGER
                The leading dimension of the array A. LDA >= max(1,N).

        TAU     (input) DOUBLE PRECISION array, dimension (N-1)
                TAU(i) must contain the scalar factor of the elementary
                reflector H(i), as returned by DGEHRD.

        WORK    (workspace/output) DOUBLE PRECISION array, dimension (MAX(1,LWORK))
                On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

        LWORK   (input) INTEGER
                The dimension of the array WORK. LWORK >= IHI-ILO.
                For optimum performance LWORK >= (IHI-ILO)*NB, 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    (output) INTEGER
                = 0:  successful exit
                < 0:  if INFO = -i, the i-th argument had an illegal value

 LAPACK routine (version 3.2)               April 2011                            DORGHR(3lapack)