294 lines
9.0 KiB
C++
294 lines
9.0 KiB
C++
/* fortran/dgetrf.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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static doublereal c_b16 = 1.;
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static doublereal c_b19 = -1.;
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/* > \brief \b DGETRF */
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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 DGETRF + dependencies */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgetrf.
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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/dgetrf.
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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/dgetrf.
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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 DGETRF( M, N, A, LDA, IPIV, INFO ) */
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/* .. Scalar Arguments .. */
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/* INTEGER INFO, LDA, M, N */
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/* .. */
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/* .. Array Arguments .. */
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/* INTEGER IPIV( * ) */
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/* DOUBLE PRECISION A( LDA, * ) */
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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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/* > DGETRF computes an LU factorization of a general M-by-N matrix A */
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/* > using partial pivoting with row interchanges. */
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/* > */
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/* > The factorization has the form */
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/* > A = P * L * U */
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/* > where P is a permutation matrix, L is lower triangular with unit */
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/* > diagonal elements (lower trapezoidal if m > n), and U is upper */
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/* > triangular (upper trapezoidal if m < n). */
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/* > */
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/* > This is the right-looking Level 3 BLAS version of the algorithm. */
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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 A. 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 A. 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 M-by-N matrix to be factored. */
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/* > On exit, the factors L and U from the factorization */
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/* > A = P*L*U; the unit diagonal elements of L are not stored. */
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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,M). */
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/* > \endverbatim */
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/* > */
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/* > \param[out] IPIV */
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/* > \verbatim */
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/* > IPIV is INTEGER array, dimension (min(M,N)) */
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/* > The pivot indices; for 1 <= i <= min(M,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[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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/* > > 0: if INFO = i, U(i,i) is exactly zero. The factorization */
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/* > has been completed, but the factor U is exactly */
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/* > singular, and division by zero will occur if it is used */
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/* > to solve a system of equations. */
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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 dgetrf_(integer *m, integer *n, doublereal *a, integer *
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lda, integer *ipiv, 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, i__3, i__4, i__5;
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/* Local variables */
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integer i__, j, jb, nb;
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extern /* Subroutine */ int dgemm_(char *, char *, integer *, integer *,
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integer *, doublereal *, doublereal *, integer *, doublereal *,
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integer *, doublereal *, doublereal *, integer *, ftnlen, ftnlen);
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integer iinfo;
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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);
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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 dlaswp_(integer *, doublereal *, integer *,
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integer *, integer *, integer *, integer *), dgetrf2_(integer *,
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integer *, doublereal *, integer *, integer *, integer *);
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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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/* .. External Functions .. */
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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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/* 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 < 0) {
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*info = -2;
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} else if (*lda < max(1,*m)) {
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*info = -4;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_((char *)"DGETRF", &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 || *n == 0) {
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return 0;
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}
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/* Determine the block size for this environment. */
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nb = ilaenv_(&c__1, (char *)"DGETRF", (char *)" ", m, n, &c_n1, &c_n1, (ftnlen)6, (ftnlen)
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1);
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if (nb <= 1 || nb >= min(*m,*n)) {
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/* Use unblocked code. */
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dgetrf2_(m, n, &a[a_offset], lda, &ipiv[1], info);
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} else {
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/* Use blocked code. */
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i__1 = min(*m,*n);
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i__2 = nb;
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for (j = 1; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) {
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/* Computing MIN */
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i__3 = min(*m,*n) - j + 1;
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jb = min(i__3,nb);
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/* Factor diagonal and subdiagonal blocks and test for exact */
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/* singularity. */
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i__3 = *m - j + 1;
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dgetrf2_(&i__3, &jb, &a[j + j * a_dim1], lda, &ipiv[j], &iinfo);
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/* Adjust INFO and the pivot indices. */
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if (*info == 0 && iinfo > 0) {
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*info = iinfo + j - 1;
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}
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/* Computing MIN */
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i__4 = *m, i__5 = j + jb - 1;
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i__3 = min(i__4,i__5);
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for (i__ = j; i__ <= i__3; ++i__) {
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ipiv[i__] = j - 1 + ipiv[i__];
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/* L10: */
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}
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/* Apply interchanges to columns 1:J-1. */
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i__3 = j - 1;
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i__4 = j + jb - 1;
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dlaswp_(&i__3, &a[a_offset], lda, &j, &i__4, &ipiv[1], &c__1);
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if (j + jb <= *n) {
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/* Apply interchanges to columns J+JB:N. */
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i__3 = *n - j - jb + 1;
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i__4 = j + jb - 1;
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dlaswp_(&i__3, &a[(j + jb) * a_dim1 + 1], lda, &j, &i__4, &
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ipiv[1], &c__1);
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/* Compute block row of U. */
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i__3 = *n - j - jb + 1;
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dtrsm_((char *)"Left", (char *)"Lower", (char *)"No transpose", (char *)"Unit", &jb, &i__3, &
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c_b16, &a[j + j * a_dim1], lda, &a[j + (j + jb) *
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a_dim1], lda, (ftnlen)4, (ftnlen)5, (ftnlen)12, (
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ftnlen)4);
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if (j + jb <= *m) {
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/* Update trailing submatrix. */
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i__3 = *m - j - jb + 1;
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i__4 = *n - j - jb + 1;
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dgemm_((char *)"No transpose", (char *)"No transpose", &i__3, &i__4, &jb,
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&c_b19, &a[j + jb + j * a_dim1], lda, &a[j + (j +
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jb) * a_dim1], lda, &c_b16, &a[j + jb + (j + jb) *
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a_dim1], lda, (ftnlen)12, (ftnlen)12);
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}
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}
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/* L20: */
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}
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}
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return 0;
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/* End of DGETRF */
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} /* dgetrf_ */
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#ifdef __cplusplus
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}
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#endif
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