convert linalg library from Fortran to C++
This commit is contained in:
Axel Kohlmeyer
254
lib/linalg/dorgl2.cpp
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254
lib/linalg/dorgl2.cpp
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/* fortran/dorgl2.f -- translated by f2c (version 20200916).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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or, if you install libf2c.a in a standard place, with -lf2c -lm
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "lmp_f2c.h"
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/* > \brief \b DORGL2 */
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/* =========== DOCUMENTATION =========== */
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/* Online html documentation available at */
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/* http://www.netlib.org/lapack/explore-html/ */
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/* > \htmlonly */
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/* > Download DORGL2 + dependencies */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dorgl2.
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f"> */
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/* > [TGZ]</a> */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dorgl2.
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f"> */
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/* > [ZIP]</a> */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dorgl2.
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f"> */
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/* > [TXT]</a> */
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/* > \endhtmlonly */
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/* Definition: */
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/* =========== */
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/* SUBROUTINE DORGL2( M, N, K, A, LDA, TAU, WORK, INFO ) */
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/* .. Scalar Arguments .. */
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/* INTEGER INFO, K, LDA, M, N */
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/* .. */
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/* .. Array Arguments .. */
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/* DOUBLE PRECISION A( LDA, * ), TAU( * ), WORK( * ) */
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/* .. */
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/* > \par Purpose: */
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/* ============= */
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/* > */
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/* > \verbatim */
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/* > */
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/* > DORGL2 generates an m by n real matrix Q with orthonormal rows, */
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/* > which is defined as the first m rows of a product of k elementary */
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/* > reflectors of order n */
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/* > */
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/* > Q = H(k) . . . H(2) H(1) */
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/* > */
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/* > as returned by DGELQF. */
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/* > \endverbatim */
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/* Arguments: */
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/* ========== */
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/* > \param[in] M */
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/* > \verbatim */
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/* > M is INTEGER */
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/* > The number of rows of the matrix Q. M >= 0. */
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/* > \endverbatim */
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/* > */
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/* > \param[in] N */
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/* > \verbatim */
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/* > N is INTEGER */
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/* > The number of columns of the matrix Q. N >= M. */
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/* > \endverbatim */
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/* > */
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/* > \param[in] K */
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/* > \verbatim */
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/* > K is INTEGER */
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/* > The number of elementary reflectors whose product defines the */
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/* > matrix Q. M >= K >= 0. */
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/* > \endverbatim */
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/* > */
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/* > \param[in,out] A */
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/* > \verbatim */
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/* > A is DOUBLE PRECISION array, dimension (LDA,N) */
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/* > On entry, the i-th row must contain the vector which defines */
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/* > the elementary reflector H(i), for i = 1,2,...,k, as returned */
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/* > by DGELQF in the first k rows of its array argument A. */
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/* > On exit, the m-by-n matrix Q. */
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/* > \endverbatim */
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/* > */
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/* > \param[in] LDA */
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/* > \verbatim */
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/* > LDA is INTEGER */
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/* > The first dimension of the array A. LDA >= max(1,M). */
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/* > \endverbatim */
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/* > */
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/* > \param[in] TAU */
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/* > \verbatim */
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/* > TAU is DOUBLE PRECISION array, dimension (K) */
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/* > TAU(i) must contain the scalar factor of the elementary */
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/* > reflector H(i), as returned by DGELQF. */
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/* > \endverbatim */
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/* > */
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/* > \param[out] WORK */
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/* > \verbatim */
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/* > WORK is DOUBLE PRECISION array, dimension (M) */
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/* > \endverbatim */
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/* > */
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/* > \param[out] INFO */
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/* > \verbatim */
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/* > INFO is INTEGER */
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/* > = 0: successful exit */
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/* > < 0: if INFO = -i, the i-th argument has an illegal value */
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/* > \endverbatim */
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/* Authors: */
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/* ======== */
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/* > \author Univ. of Tennessee */
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/* > \author Univ. of California Berkeley */
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/* > \author Univ. of Colorado Denver */
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/* > \author NAG Ltd. */
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/* > \ingroup doubleOTHERcomputational */
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/* ===================================================================== */
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/* Subroutine */ int dorgl2_(integer *m, integer *n, integer *k, doublereal *
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a, integer *lda, doublereal *tau, doublereal *work, integer *info)
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{
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/* System generated locals */
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integer a_dim1, a_offset, i__1, i__2;
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doublereal d__1;
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/* Local variables */
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integer i__, j, l;
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extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *,
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integer *), dlarf_(char *, integer *, integer *, doublereal *,
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integer *, doublereal *, doublereal *, integer *, doublereal *,
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ftnlen), xerbla_(char *, integer *, ftnlen);
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/* -- LAPACK computational routine -- */
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/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
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/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* ===================================================================== */
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/* .. Parameters .. */
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/* .. */
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/* .. Local Scalars .. */
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/* .. */
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/* .. External Subroutines .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. Executable Statements .. */
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/* Test the input arguments */
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/* Parameter adjustments */
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a_dim1 = *lda;
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a_offset = 1 + a_dim1;
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a -= a_offset;
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--tau;
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--work;
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/* Function Body */
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*info = 0;
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if (*m < 0) {
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*info = -1;
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} else if (*n < *m) {
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*info = -2;
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} else if (*k < 0 || *k > *m) {
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*info = -3;
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} else if (*lda < max(1,*m)) {
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*info = -5;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_((char *)"DORGL2", &i__1, (ftnlen)6);
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return 0;
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}
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/* Quick return if possible */
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if (*m <= 0) {
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return 0;
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}
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if (*k < *m) {
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/* Initialise rows k+1:m to rows of the unit matrix */
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i__1 = *n;
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for (j = 1; j <= i__1; ++j) {
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i__2 = *m;
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for (l = *k + 1; l <= i__2; ++l) {
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a[l + j * a_dim1] = 0.;
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/* L10: */
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}
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if (j > *k && j <= *m) {
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a[j + j * a_dim1] = 1.;
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}
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/* L20: */
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}
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}
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for (i__ = *k; i__ >= 1; --i__) {
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/* Apply H(i) to A(i:m,i:n) from the right */
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if (i__ < *n) {
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if (i__ < *m) {
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a[i__ + i__ * a_dim1] = 1.;
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i__1 = *m - i__;
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i__2 = *n - i__ + 1;
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dlarf_((char *)"Right", &i__1, &i__2, &a[i__ + i__ * a_dim1], lda, &
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tau[i__], &a[i__ + 1 + i__ * a_dim1], lda, &work[1], (
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ftnlen)5);
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}
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i__1 = *n - i__;
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d__1 = -tau[i__];
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dscal_(&i__1, &d__1, &a[i__ + (i__ + 1) * a_dim1], lda);
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}
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a[i__ + i__ * a_dim1] = 1. - tau[i__];
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/* Set A(i,1:i-1) to zero */
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i__1 = i__ - 1;
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for (l = 1; l <= i__1; ++l) {
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a[i__ + l * a_dim1] = 0.;
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/* L30: */
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}
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/* L40: */
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}
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return 0;
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/* End of DORGL2 */
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} /* dorgl2_ */
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#ifdef __cplusplus
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}
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#endif
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