/*  -- translated by f2c (version 20100827).
   You must link the resulting object file with libf2c:
	on Microsoft Windows system, link with libf2c.lib;
	on Linux or Unix systems, link with .../path/to/libf2c.a -lm
	or, if you install libf2c.a in a standard place, with -lf2c -lm
	-- in that order, at the end of the command line, as in
		cc *.o -lf2c -lm
	Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,

		http://www.netlib.org/f2c/libf2c.zip
*/

#include "f2c.h"

/* Table of constant values */

static integer c__1 = 1;
static integer c_n1 = -1;
static integer c__2 = 2;

/* Subroutine */ int igraphdormhr_(char *side, char *trans, integer *m, integer *n, 
	integer *ilo, integer *ihi, doublereal *a, integer *lda, doublereal *
	tau, doublereal *c__, integer *ldc, doublereal *work, integer *lwork, 
	integer *info)
{
    /* System generated locals */
    address a__1[2];
    integer a_dim1, a_offset, c_dim1, c_offset, i__1[2], i__2;
    char ch__1[2];

    /* Builtin functions   
       Subroutine */ int s_cat(char *, char **, integer *, integer *, ftnlen);

    /* Local variables */
    integer i1, i2, nb, mi, nh, ni, nq, nw;
    logical left;
    extern logical igraphlsame_(char *, char *);
    integer iinfo;
    extern /* Subroutine */ int igraphxerbla_(char *, integer *, ftnlen);
    extern integer igraphilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *, ftnlen, ftnlen);
    extern /* Subroutine */ int igraphdormqr_(char *, char *, integer *, integer *, 
	    integer *, doublereal *, integer *, doublereal *, doublereal *, 
	    integer *, doublereal *, integer *, integer *);
    integer lwkopt;
    logical lquery;


/*  -- LAPACK routine (version 3.2) --   
    -- LAPACK is a software package provided by Univ. of Tennessee,    --   
    -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--   
       November 2006   


    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).   

    Arguments   
    =========   

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

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

    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.   

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

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

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

    =====================================================================   


       Test the input arguments   

       Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --tau;
    c_dim1 = *ldc;
    c_offset = 1 + c_dim1;
    c__ -= c_offset;
    --work;

    /* Function Body */
    *info = 0;
    nh = *ihi - *ilo;
    left = igraphlsame_(side, "L");
    lquery = *lwork == -1;

/*     NQ is the order of Q and NW is the minimum dimension of WORK */

    if (left) {
	nq = *m;
	nw = *n;
    } else {
	nq = *n;
	nw = *m;
    }
    if (! left && ! igraphlsame_(side, "R")) {
	*info = -1;
    } else if (! igraphlsame_(trans, "N") && ! igraphlsame_(trans, 
	    "T")) {
	*info = -2;
    } else if (*m < 0) {
	*info = -3;
    } else if (*n < 0) {
	*info = -4;
    } else if (*ilo < 1 || *ilo > max(1,nq)) {
	*info = -5;
    } else if (*ihi < min(*ilo,nq) || *ihi > nq) {
	*info = -6;
    } else if (*lda < max(1,nq)) {
	*info = -8;
    } else if (*ldc < max(1,*m)) {
	*info = -11;
    } else if (*lwork < max(1,nw) && ! lquery) {
	*info = -13;
    }

    if (*info == 0) {
	if (left) {
/* Writing concatenation */
	    i__1[0] = 1, a__1[0] = side;
	    i__1[1] = 1, a__1[1] = trans;
	    s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
	    nb = igraphilaenv_(&c__1, "DORMQR", ch__1, &nh, n, &nh, &c_n1, (ftnlen)
		    6, (ftnlen)2);
	} else {
/* Writing concatenation */
	    i__1[0] = 1, a__1[0] = side;
	    i__1[1] = 1, a__1[1] = trans;
	    s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
	    nb = igraphilaenv_(&c__1, "DORMQR", ch__1, m, &nh, &nh, &c_n1, (ftnlen)
		    6, (ftnlen)2);
	}
	lwkopt = max(1,nw) * nb;
	work[1] = (doublereal) lwkopt;
    }

    if (*info != 0) {
	i__2 = -(*info);
	igraphxerbla_("DORMHR", &i__2, (ftnlen)6);
	return 0;
    } else if (lquery) {
	return 0;
    }

/*     Quick return if possible */

    if (*m == 0 || *n == 0 || nh == 0) {
	work[1] = 1.;
	return 0;
    }

    if (left) {
	mi = nh;
	ni = *n;
	i1 = *ilo + 1;
	i2 = 1;
    } else {
	mi = *m;
	ni = nh;
	i1 = 1;
	i2 = *ilo + 1;
    }

    igraphdormqr_(side, trans, &mi, &ni, &nh, &a[*ilo + 1 + *ilo * a_dim1], lda, &
	    tau[*ilo], &c__[i1 + i2 * c_dim1], ldc, &work[1], lwork, &iinfo);

    work[1] = (doublereal) lwkopt;
    return 0;

/*     End of DORMHR */

} /* igraphdormhr_ */

