/*  -- 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;

/* Subroutine */ int igraphdorm2l_(char *side, char *trans, integer *m, integer *n, 
	integer *k, doublereal *a, integer *lda, doublereal *tau, doublereal *
	c__, integer *ldc, doublereal *work, integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, c_dim1, c_offset, i__1, i__2;

    /* Local variables */
    integer i__, i1, i2, i3, mi, ni, nq;
    doublereal aii;
    logical left;
    extern /* Subroutine */ int igraphdlarf_(char *, integer *, integer *, 
	    doublereal *, integer *, doublereal *, doublereal *, integer *, 
	    doublereal *);
    extern logical igraphlsame_(char *, char *);
    extern /* Subroutine */ int igraphxerbla_(char *, integer *, ftnlen);
    logical notran;


/*  -- LAPACK routine (version 3.3.1) --   
    -- LAPACK is a software package provided by Univ. of Tennessee,    --   
    -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--   
    -- April 2011                                                      --   


    Purpose   
    =======   

    DORM2L overwrites the general real m by n matrix C with   

          Q * C  if SIDE = 'L' and TRANS = 'N', or   

          Q**T * C  if SIDE = 'L' and TRANS = 'T', or   

          C * Q  if SIDE = 'R' and TRANS = 'N', or   

          C * Q**T if SIDE = 'R' and TRANS = 'T',   

    where Q is a real orthogonal matrix defined as the product of k   
    elementary reflectors   

          Q = H(k) . . . H(2) H(1)   

    as returned by DGEQLF. Q is of order m if SIDE = 'L' and of order n   
    if SIDE = 'R'.   

    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': apply Q  (No transpose)   
            = 'T': apply Q**T (Transpose)   

    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.   

    K       (input) INTEGER   
            The number of elementary reflectors whose product defines   
            the matrix Q.   
            If SIDE = 'L', M >= K >= 0;   
            if SIDE = 'R', N >= K >= 0.   

    A       (input) 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   
            DGEQLF in the last k columns of its array argument A.   
            A is modified by the routine but restored on exit.   

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

    TAU     (input) DOUBLE PRECISION array, dimension (K)   
            TAU(i) must contain the scalar factor of the elementary   
            reflector H(i), as returned by DGEQLF.   

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

    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;
    left = igraphlsame_(side, "L");
    notran = igraphlsame_(trans, "N");

/*     NQ is the order of Q */

    if (left) {
	nq = *m;
    } else {
	nq = *n;
    }
    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;
    }
    if (*info != 0) {
	i__1 = -(*info);
	igraphxerbla_("DORM2L", &i__1, (ftnlen)6);
	return 0;
    }

/*     Quick return if possible */

    if (*m == 0 || *n == 0 || *k == 0) {
	return 0;
    }

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

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

    i__1 = i2;
    i__2 = i3;
    for (i__ = i1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
	if (left) {

/*           H(i) is applied to C(1:m-k+i,1:n) */

	    mi = *m - *k + i__;
	} else {

/*           H(i) is applied to C(1:m,1:n-k+i) */

	    ni = *n - *k + i__;
	}

/*        Apply H(i) */

	aii = a[nq - *k + i__ + i__ * a_dim1];
	a[nq - *k + i__ + i__ * a_dim1] = 1.;
	igraphdlarf_(side, &mi, &ni, &a[i__ * a_dim1 + 1], &c__1, &tau[i__], &c__[
		c_offset], ldc, &work[1]);
	a[nq - *k + i__ + i__ * a_dim1] = aii;
/* L10: */
    }
    return 0;

/*     End of DORM2L */

} /* igraphdorm2l_ */

