332 lines
9.6 KiB
C++
332 lines
9.6 KiB
C++
/* fortran/dorgtr.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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/* Table of constant values */
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static integer c__1 = 1;
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static integer c_n1 = -1;
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/* > \brief \b DORGTR */
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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 DORGTR + dependencies */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dorgtr.
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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/dorgtr.
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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/dorgtr.
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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 DORGTR( UPLO, N, A, LDA, TAU, WORK, LWORK, INFO ) */
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/* .. Scalar Arguments .. */
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/* CHARACTER UPLO */
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/* INTEGER INFO, LDA, LWORK, 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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/* > DORGTR generates a real orthogonal matrix Q which is defined as the */
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/* > product of n-1 elementary reflectors of order N, as returned by */
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/* > DSYTRD: */
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/* > */
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/* > if UPLO = 'U', Q = H(n-1) . . . H(2) H(1), */
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/* > */
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/* > if UPLO = 'L', Q = H(1) H(2) . . . H(n-1). */
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/* > \endverbatim */
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/* Arguments: */
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/* ========== */
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/* > \param[in] UPLO */
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/* > \verbatim */
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/* > UPLO is CHARACTER*1 */
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/* > = 'U': Upper triangle of A contains elementary reflectors */
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/* > from DSYTRD; */
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/* > = 'L': Lower triangle of A contains elementary reflectors */
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/* > from DSYTRD. */
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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 order of the matrix Q. N >= 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 vectors which define the elementary reflectors, */
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/* > as returned by DSYTRD. */
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/* > On exit, the N-by-N orthogonal 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 leading dimension of the array A. LDA >= max(1,N). */
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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 (N-1) */
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/* > TAU(i) must contain the scalar factor of the elementary */
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/* > reflector H(i), as returned by DSYTRD. */
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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 (MAX(1,LWORK)) */
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/* > On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */
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/* > \endverbatim */
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/* > */
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/* > \param[in] LWORK */
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/* > \verbatim */
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/* > LWORK is INTEGER */
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/* > The dimension of the array WORK. LWORK >= max(1,N-1). */
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/* > For optimum performance LWORK >= (N-1)*NB, where NB is */
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/* > the optimal blocksize. */
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/* > */
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/* > If LWORK = -1, then a workspace query is assumed; the routine */
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/* > only calculates the optimal size of the WORK array, returns */
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/* > this value as the first entry of the WORK array, and no error */
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/* > message related to LWORK is issued by XERBLA. */
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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 had 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 dorgtr_(char *uplo, integer *n, doublereal *a, integer *
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lda, doublereal *tau, doublereal *work, integer *lwork, integer *info,
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ftnlen uplo_len)
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{
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/* System generated locals */
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integer a_dim1, a_offset, i__1, i__2, i__3;
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/* Local variables */
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integer i__, j, nb;
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extern logical lsame_(char *, char *, ftnlen, ftnlen);
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integer iinfo;
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logical upper;
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extern /* Subroutine */ int xerbla_(char *, integer *, ftnlen);
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extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
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integer *, integer *, ftnlen, ftnlen);
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extern /* Subroutine */ int dorgql_(integer *, integer *, integer *,
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doublereal *, integer *, doublereal *, doublereal *, integer *,
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integer *), dorgqr_(integer *, integer *, integer *, doublereal *,
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integer *, doublereal *, doublereal *, integer *, integer *);
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integer lwkopt;
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logical lquery;
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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 Functions .. */
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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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lquery = *lwork == -1;
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upper = lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1);
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if (! upper && ! lsame_(uplo, (char *)"L", (ftnlen)1, (ftnlen)1)) {
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*info = -1;
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} else if (*n < 0) {
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*info = -2;
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} else if (*lda < max(1,*n)) {
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*info = -4;
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} else /* if(complicated condition) */ {
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/* Computing MAX */
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i__1 = 1, i__2 = *n - 1;
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if (*lwork < max(i__1,i__2) && ! lquery) {
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*info = -7;
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}
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}
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if (*info == 0) {
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if (upper) {
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i__1 = *n - 1;
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i__2 = *n - 1;
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i__3 = *n - 1;
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nb = ilaenv_(&c__1, (char *)"DORGQL", (char *)" ", &i__1, &i__2, &i__3, &c_n1, (
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ftnlen)6, (ftnlen)1);
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} else {
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i__1 = *n - 1;
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i__2 = *n - 1;
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i__3 = *n - 1;
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nb = ilaenv_(&c__1, (char *)"DORGQR", (char *)" ", &i__1, &i__2, &i__3, &c_n1, (
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ftnlen)6, (ftnlen)1);
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}
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/* Computing MAX */
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i__1 = 1, i__2 = *n - 1;
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lwkopt = max(i__1,i__2) * nb;
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work[1] = (doublereal) lwkopt;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_((char *)"DORGTR", &i__1, (ftnlen)6);
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return 0;
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} else if (lquery) {
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return 0;
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}
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/* Quick return if possible */
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if (*n == 0) {
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work[1] = 1.;
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return 0;
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}
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if (upper) {
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/* Q was determined by a call to DSYTRD with UPLO = 'U' */
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/* Shift the vectors which define the elementary reflectors one */
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/* column to the left, and set the last row and column of Q to */
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/* those of the unit matrix */
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i__1 = *n - 1;
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for (j = 1; j <= i__1; ++j) {
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i__2 = j - 1;
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for (i__ = 1; i__ <= i__2; ++i__) {
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a[i__ + j * a_dim1] = a[i__ + (j + 1) * a_dim1];
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/* L10: */
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}
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a[*n + j * a_dim1] = 0.;
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/* L20: */
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}
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i__1 = *n - 1;
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for (i__ = 1; i__ <= i__1; ++i__) {
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a[i__ + *n * a_dim1] = 0.;
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/* L30: */
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}
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a[*n + *n * a_dim1] = 1.;
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/* Generate Q(1:n-1,1:n-1) */
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i__1 = *n - 1;
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i__2 = *n - 1;
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i__3 = *n - 1;
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dorgql_(&i__1, &i__2, &i__3, &a[a_offset], lda, &tau[1], &work[1],
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lwork, &iinfo);
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} else {
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/* Q was determined by a call to DSYTRD with UPLO = 'L'. */
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/* Shift the vectors which define the elementary reflectors one */
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/* column to the right, and set the first row and column of Q to */
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/* those of the unit matrix */
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for (j = *n; j >= 2; --j) {
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a[j * a_dim1 + 1] = 0.;
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i__1 = *n;
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for (i__ = j + 1; i__ <= i__1; ++i__) {
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a[i__ + j * a_dim1] = a[i__ + (j - 1) * a_dim1];
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/* L40: */
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}
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/* L50: */
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}
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a[a_dim1 + 1] = 1.;
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i__1 = *n;
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for (i__ = 2; i__ <= i__1; ++i__) {
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a[i__ + a_dim1] = 0.;
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/* L60: */
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}
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if (*n > 1) {
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/* Generate Q(2:n,2:n) */
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i__1 = *n - 1;
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i__2 = *n - 1;
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i__3 = *n - 1;
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dorgqr_(&i__1, &i__2, &i__3, &a[(a_dim1 << 1) + 2], lda, &tau[1],
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&work[1], lwork, &iinfo);
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}
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}
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work[1] = (doublereal) lwkopt;
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return 0;
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/* End of DORGTR */
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} /* dorgtr_ */
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#ifdef __cplusplus
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}
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#endif
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