convert linalg library from Fortran to C++
This commit is contained in:
Axel Kohlmeyer
272
lib/linalg/dgetrs.cpp
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272
lib/linalg/dgetrs.cpp
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/* fortran/dgetrs.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 doublereal c_b12 = 1.;
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static integer c_n1 = -1;
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/* > \brief \b DGETRS */
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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 DGETRS + dependencies */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgetrs.
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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/dgetrs.
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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/dgetrs.
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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 DGETRS( TRANS, N, NRHS, A, LDA, IPIV, B, LDB, INFO ) */
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/* .. Scalar Arguments .. */
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/* CHARACTER TRANS */
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/* INTEGER INFO, LDA, LDB, N, NRHS */
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/* .. */
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/* .. Array Arguments .. */
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/* INTEGER IPIV( * ) */
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/* DOUBLE PRECISION A( LDA, * ), B( LDB, * ) */
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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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/* > DGETRS solves a system of linear equations */
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/* > A * X = B or A**T * X = B */
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/* > with a general N-by-N matrix A using the LU factorization computed */
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/* > by DGETRF. */
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/* > \endverbatim */
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/* Arguments: */
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/* ========== */
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/* > \param[in] TRANS */
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/* > \verbatim */
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/* > TRANS is CHARACTER*1 */
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/* > Specifies the form of the system of equations: */
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/* > = 'N': A * X = B (No transpose) */
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/* > = 'T': A**T* X = B (Transpose) */
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/* > = 'C': A**T* X = B (Conjugate transpose = Transpose) */
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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 A. N >= 0. */
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/* > \endverbatim */
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/* > */
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/* > \param[in] NRHS */
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/* > \verbatim */
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/* > NRHS is INTEGER */
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/* > The number of right hand sides, i.e., the number of columns */
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/* > of the matrix B. NRHS >= 0. */
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/* > \endverbatim */
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/* > */
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/* > \param[in] A */
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/* > \verbatim */
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/* > A is DOUBLE PRECISION array, dimension (LDA,N) */
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/* > The factors L and U from the factorization A = P*L*U */
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/* > as computed by DGETRF. */
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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] IPIV */
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/* > \verbatim */
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/* > IPIV is INTEGER array, dimension (N) */
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/* > The pivot indices from DGETRF; for 1<=i<=N, row i of the */
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/* > matrix was interchanged with row IPIV(i). */
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/* > \endverbatim */
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/* > */
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/* > \param[in,out] B */
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/* > \verbatim */
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/* > B is DOUBLE PRECISION array, dimension (LDB,NRHS) */
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/* > On entry, the right hand side matrix B. */
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/* > On exit, the solution matrix X. */
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/* > \endverbatim */
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/* > */
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/* > \param[in] LDB */
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/* > \verbatim */
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/* > LDB is INTEGER */
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/* > The leading dimension of the array B. LDB >= max(1,N). */
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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 doubleGEcomputational */
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/* ===================================================================== */
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/* Subroutine */ int dgetrs_(char *trans, integer *n, integer *nrhs,
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doublereal *a, integer *lda, integer *ipiv, doublereal *b, integer *
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ldb, integer *info, ftnlen trans_len)
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{
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/* System generated locals */
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integer a_dim1, a_offset, b_dim1, b_offset, i__1;
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/* Local variables */
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extern logical lsame_(char *, char *, ftnlen, ftnlen);
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extern /* Subroutine */ int dtrsm_(char *, char *, char *, char *,
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integer *, integer *, doublereal *, doublereal *, integer *,
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doublereal *, integer *, ftnlen, ftnlen, ftnlen, ftnlen), xerbla_(
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char *, integer *, ftnlen), dlaswp_(integer *, doublereal *,
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integer *, integer *, integer *, integer *, integer *);
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logical notran;
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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 parameters. */
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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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--ipiv;
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b_dim1 = *ldb;
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b_offset = 1 + b_dim1;
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b -= b_offset;
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/* Function Body */
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*info = 0;
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notran = lsame_(trans, (char *)"N", (ftnlen)1, (ftnlen)1);
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if (! notran && ! lsame_(trans, (char *)"T", (ftnlen)1, (ftnlen)1) && ! lsame_(
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trans, (char *)"C", (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 (*nrhs < 0) {
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*info = -3;
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} else if (*lda < max(1,*n)) {
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*info = -5;
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} else if (*ldb < max(1,*n)) {
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*info = -8;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_((char *)"DGETRS", &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 (*n == 0 || *nrhs == 0) {
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return 0;
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}
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if (notran) {
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/* Solve A * X = B. */
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/* Apply row interchanges to the right hand sides. */
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dlaswp_(nrhs, &b[b_offset], ldb, &c__1, n, &ipiv[1], &c__1);
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/* Solve L*X = B, overwriting B with X. */
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dtrsm_((char *)"Left", (char *)"Lower", (char *)"No transpose", (char *)"Unit", n, nrhs, &c_b12, &a[
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a_offset], lda, &b[b_offset], ldb, (ftnlen)4, (ftnlen)5, (
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ftnlen)12, (ftnlen)4);
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/* Solve U*X = B, overwriting B with X. */
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dtrsm_((char *)"Left", (char *)"Upper", (char *)"No transpose", (char *)"Non-unit", n, nrhs, &c_b12, &
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a[a_offset], lda, &b[b_offset], ldb, (ftnlen)4, (ftnlen)5, (
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ftnlen)12, (ftnlen)8);
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} else {
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/* Solve A**T * X = B. */
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/* Solve U**T *X = B, overwriting B with X. */
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dtrsm_((char *)"Left", (char *)"Upper", (char *)"Transpose", (char *)"Non-unit", n, nrhs, &c_b12, &a[
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a_offset], lda, &b[b_offset], ldb, (ftnlen)4, (ftnlen)5, (
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ftnlen)9, (ftnlen)8);
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/* Solve L**T *X = B, overwriting B with X. */
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dtrsm_((char *)"Left", (char *)"Lower", (char *)"Transpose", (char *)"Unit", n, nrhs, &c_b12, &a[
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a_offset], lda, &b[b_offset], ldb, (ftnlen)4, (ftnlen)5, (
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ftnlen)9, (ftnlen)4);
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/* Apply row interchanges to the solution vectors. */
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dlaswp_(nrhs, &b[b_offset], ldb, &c__1, n, &ipiv[1], &c_n1);
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}
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return 0;
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/* End of DGETRS */
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} /* dgetrs_ */
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#ifdef __cplusplus
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}
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#endif
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