/*  -- translated by f2c (version 20240504).
   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;
static integer c__65 = 65;

/* > \brief \b DORMQR   

    =========== DOCUMENTATION ===========   

   Online html documentation available at   
              http://www.netlib.org/lapack/explore-html/   

   > \htmlonly   
   > Download DORMQR + dependencies   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dormqr.
f">   
   > [TGZ]</a>   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dormqr.
f">   
   > [ZIP]</a>   
   > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dormqr.
f">   
   > [TXT]</a>   
   > \endhtmlonly   

    Definition:   
    ===========   

         SUBROUTINE DORMQR( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC,   
                            WORK, LWORK, INFO )   

         CHARACTER          SIDE, TRANS   
         INTEGER            INFO, K, LDA, LDC, LWORK, M, N   
         DOUBLE PRECISION   A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )   


   > \par Purpose:   
    =============   
   >   
   > \verbatim   
   >   
   > DORMQR 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 defined as the product of k   
   > elementary reflectors   
   >   
   >       Q = H(1) H(2) . . . H(k)   
   >   
   > as returned by DGEQRF. Q is of order M if SIDE = 'L' and of order N   
   > if SIDE = 'R'.   
   > \endverbatim   

    Arguments:   
    ==========   

   > \param[in] SIDE   
   > \verbatim   
   >          SIDE is CHARACTER*1   
   >          = 'L': apply Q or Q**T from the Left;   
   >          = 'R': apply Q or Q**T from the Right.   
   > \endverbatim   
   >   
   > \param[in] TRANS   
   > \verbatim   
   >          TRANS is CHARACTER*1   
   >          = 'N':  No transpose, apply Q;   
   >          = 'T':  Transpose, apply Q**T.   
   > \endverbatim   
   >   
   > \param[in] M   
   > \verbatim   
   >          M is INTEGER   
   >          The number of rows of the matrix C. M >= 0.   
   > \endverbatim   
   >   
   > \param[in] N   
   > \verbatim   
   >          N is INTEGER   
   >          The number of columns of the matrix C. N >= 0.   
   > \endverbatim   
   >   
   > \param[in] K   
   > \verbatim   
   >          K is INTEGER   
   >          The number of elementary reflectors whose product defines   
   >          the matrix Q.   
   >          If SIDE = 'L', M >= K >= 0;   
   >          if SIDE = 'R', N >= K >= 0.   
   > \endverbatim   
   >   
   > \param[in] A   
   > \verbatim   
   >          A is DOUBLE PRECISION array, dimension (LDA,K)   
   >          The i-th column must contain the vector which defines the   
   >          elementary reflector H(i), for i = 1,2,...,k, as returned by   
   >          DGEQRF in the first k columns of its array argument A.   
   > \endverbatim   
   >   
   > \param[in] LDA   
   > \verbatim   
   >          LDA is INTEGER   
   >          The leading dimension of the array A.   
   >          If SIDE = 'L', LDA >= max(1,M);   
   >          if SIDE = 'R', LDA >= max(1,N).   
   > \endverbatim   
   >   
   > \param[in] TAU   
   > \verbatim   
   >          TAU is DOUBLE PRECISION array, dimension (K)   
   >          TAU(i) must contain the scalar factor of the elementary   
   >          reflector H(i), as returned by DGEQRF.   
   > \endverbatim   
   >   
   > \param[in,out] C   
   > \verbatim   
   >          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.   
   > \endverbatim   
   >   
   > \param[in] LDC   
   > \verbatim   
   >          LDC is INTEGER   
   >          The leading dimension of the array C. LDC >= max(1,M).   
   > \endverbatim   
   >   
   > \param[out] WORK   
   > \verbatim   
   >          WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))   
   >          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.   
   > \endverbatim   
   >   
   > \param[in] LWORK   
   > \verbatim   
   >          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.   
   > \endverbatim   
   >   
   > \param[out] INFO   
   > \verbatim   
   >          INFO is INTEGER   
   >          = 0:  successful exit   
   >          < 0:  if INFO = -i, the i-th argument had an illegal value   
   > \endverbatim   

    Authors:   
    ========   

   > \author Univ. of Tennessee   
   > \author Univ. of California Berkeley   
   > \author Univ. of Colorado Denver   
   > \author NAG Ltd.   

   > \date November 2011   

   > \ingroup doubleOTHERcomputational   

    =====================================================================   
   Subroutine */ int igraphdormqr_(char *side, char *trans, integer *m, integer *n, 
	integer *k, 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, i__2, i__3[2], i__4, 
	    i__5;
    char ch__1[2];

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

    /* Local variables */
    integer i__;
    doublereal t[4160]	/* was [65][64] */;
    integer i1, i2, i3, ib, ic, jc, nb, mi, ni, nq, nw, iws;
    logical left;
    extern logical igraphlsame_(char *, char *);
    integer nbmin, iinfo;
    extern /* Subroutine */ int igraphdorm2r_(char *, char *, integer *, integer *, 
	    integer *, doublereal *, integer *, doublereal *, doublereal *, 
	    integer *, doublereal *, integer *), igraphdlarfb_(char 
	    *, char *, char *, char *, integer *, integer *, integer *, 
	    doublereal *, integer *, doublereal *, integer *, doublereal *, 
	    integer *, doublereal *, integer *), igraphdlarft_(char *, char *, integer *, integer *, doublereal 
	    *, integer *, doublereal *, doublereal *, integer *), igraphxerbla_(char *, integer *, ftnlen);
    extern integer igraphilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *, ftnlen, ftnlen);
    logical notran;
    integer ldwork, lwkopt;
    logical lquery;


/*  -- LAPACK computational routine (version 3.4.0) --   
    -- LAPACK is a software package provided by Univ. of Tennessee,    --   
    -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--   
       November 2011   


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


       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;
    left = igraphlsame_(side, "L");
    notran = igraphlsame_(trans, "N");
    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 (! notran && ! igraphlsame_(trans, "T")) {
	*info = -2;
    } else if (*m < 0) {
	*info = -3;
    } else if (*n < 0) {
	*info = -4;
    } else if (*k < 0 || *k > nq) {
	*info = -5;
    } else if (*lda < max(1,nq)) {
	*info = -7;
    } else if (*ldc < max(1,*m)) {
	*info = -10;
    } else if (*lwork < max(1,nw) && ! lquery) {
	*info = -12;
    }

    if (*info == 0) {

/*        Determine the block size.  NB may be at most NBMAX, where NBMAX   
          is used to define the local array T.   

   Computing MIN   
   Writing concatenation */
	i__3[0] = 1, a__1[0] = side;
	i__3[1] = 1, a__1[1] = trans;
	s_cat(ch__1, a__1, i__3, &c__2, (ftnlen)2);
	i__1 = 64, i__2 = igraphilaenv_(&c__1, "DORMQR", ch__1, m, n, k, &c_n1, (
		ftnlen)6, (ftnlen)2);
	nb = min(i__1,i__2);
	lwkopt = max(1,nw) * nb;
	work[1] = (doublereal) lwkopt;
    }

    if (*info != 0) {
	i__1 = -(*info);
	igraphxerbla_("DORMQR", &i__1, (ftnlen)6);
	return 0;
    } else if (lquery) {
	return 0;
    }

/*     Quick return if possible */

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

    nbmin = 2;
    ldwork = nw;
    if (nb > 1 && nb < *k) {
	iws = nw * nb;
	if (*lwork < iws) {
	    nb = *lwork / ldwork;
/* Computing MAX   
   Writing concatenation */
	    i__3[0] = 1, a__1[0] = side;
	    i__3[1] = 1, a__1[1] = trans;
	    s_cat(ch__1, a__1, i__3, &c__2, (ftnlen)2);
	    i__1 = 2, i__2 = igraphilaenv_(&c__2, "DORMQR", ch__1, m, n, k, &c_n1, (
		    ftnlen)6, (ftnlen)2);
	    nbmin = max(i__1,i__2);
	}
    } else {
	iws = nw;
    }

    if (nb < nbmin || nb >= *k) {

/*        Use unblocked code */

	igraphdorm2r_(side, trans, m, n, k, &a[a_offset], lda, &tau[1], &c__[
		c_offset], ldc, &work[1], &iinfo);
    } else {

/*        Use blocked code */

	if (left && ! notran || ! left && notran) {
	    i1 = 1;
	    i2 = *k;
	    i3 = nb;
	} else {
	    i1 = (*k - 1) / nb * nb + 1;
	    i2 = 1;
	    i3 = -nb;
	}

	if (left) {
	    ni = *n;
	    jc = 1;
	} else {
	    mi = *m;
	    ic = 1;
	}

	i__1 = i2;
	i__2 = i3;
	for (i__ = i1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
/* Computing MIN */
	    i__4 = nb, i__5 = *k - i__ + 1;
	    ib = min(i__4,i__5);

/*           Form the triangular factor of the block reflector   
             H = H(i) H(i+1) . . . H(i+ib-1) */

	    i__4 = nq - i__ + 1;
	    igraphdlarft_("Forward", "Columnwise", &i__4, &ib, &a[i__ + i__ * 
		    a_dim1], lda, &tau[i__], t, &c__65)
		    ;
	    if (left) {

/*              H or H**T is applied to C(i:m,1:n) */

		mi = *m - i__ + 1;
		ic = i__;
	    } else {

/*              H or H**T is applied to C(1:m,i:n) */

		ni = *n - i__ + 1;
		jc = i__;
	    }

/*           Apply H or H**T */

	    igraphdlarfb_(side, trans, "Forward", "Columnwise", &mi, &ni, &ib, &a[
		    i__ + i__ * a_dim1], lda, t, &c__65, &c__[ic + jc * 
		    c_dim1], ldc, &work[1], &ldwork);
/* L10: */
	}
    }
    work[1] = (doublereal) lwkopt;
    return 0;

/*     End of DORMQR */

} /* igraphdormqr_ */

