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/* ../netlib/dormr2.f -- 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 "FLA_f2c.h" /* > \brief \b DORMR2 multiplies a general matrix by the orthogonal matrix from a RQ factorization determined by sgerqf (unblocked algorithm). */
/* =========== DOCUMENTATION =========== */
/* Online html documentation available at */
/* http://www.netlib.org/lapack/explore-html/ */
/* > \htmlonly */
/* > Download DORMR2 + dependencies */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dormr2. f"> */
/* > [TGZ]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dormr2. f"> */
/* > [ZIP]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dormr2. f"> */
/* > [TXT]</a> */
/* > \endhtmlonly */
/* Definition: */
/* =========== */
/* SUBROUTINE DORMR2( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, */
/* WORK, INFO ) */
/* .. Scalar Arguments .. */
/* CHARACTER SIDE, TRANS */
/* INTEGER INFO, K, LDA, LDC, M, N */
/* .. */
/* .. Array Arguments .. */
/* DOUBLE PRECISION A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * ) */
/* .. */
/* > \par Purpose: */
/* ============= */
/* > */
/* > \verbatim */
/* > */
/* > DORMR2 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(1) H(2) . . . H(k) */
/* > */
/* > as returned by DGERQF. 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': apply Q (No transpose) */
/* > = 'T': apply Q' (Transpose) */
/* > \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,M) if SIDE = 'L', */
/* > (LDA,N) if SIDE = 'R' */
/* > The i-th row must contain the vector which defines the */
/* > elementary reflector H(i), for i = 1,2,...,k, as returned by */
/* > DGERQF in the last k rows of its array argument A. */
/* > A is modified by the routine but restored on exit. */
/* > \endverbatim */
/* > */
/* > \param[in] LDA */
/* > \verbatim */
/* > LDA is INTEGER */
/* > The leading dimension of the array A. LDA >= max(1,K). */
/* > \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 DGERQF. */
/* > \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 */
/* > (N) if SIDE = 'L', */
/* > (M) if SIDE = 'R' */
/* > \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 September 2012 */
/* > \ingroup doubleOTHERcomputational */
/* ===================================================================== */
/* Subroutine */
int dormr2_(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 dlarf_(char *, integer *, integer *, doublereal *, integer *, doublereal *, doublereal *, integer *, doublereal *);
extern logical lsame_(char *, char *);
extern /* Subroutine */
int xerbla_(char *, integer *);
logical notran;
/* -- LAPACK computational routine (version 3.4.2) -- */
/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/* September 2012 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* 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 = lsame_(side, "L");
notran = lsame_(trans, "N");
/* NQ is the order of Q */
if (left)
{
nq = *m;
}
else
{
nq = *n;
}
if (! left && ! lsame_(side, "R"))
{
*info = -1;
}
else if (! notran && ! lsame_(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,*k))
{
*info = -7;
}
else if (*ldc < max(1,*m))
{
*info = -10;
}
if (*info != 0)
{
i__1 = -(*info);
xerbla_("DORMR2", &i__1);
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[i__ + (nq - *k + i__) * a_dim1];
a[i__ + (nq - *k + i__) * a_dim1] = 1.;
dlarf_(side, &mi, &ni, &a[i__ + a_dim1], lda, &tau[i__], &c__[ c_offset], ldc, &work[1]);
a[i__ + (nq - *k + i__) * a_dim1] = aii;
/* L10: */
}
return 0;
/* End of DORMR2 */
}
/* dormr2_ */
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