convert linalg library from Fortran to C++
This commit is contained in:
431
lib/linalg/dgebrd.cpp
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431
lib/linalg/dgebrd.cpp
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/* fortran/dgebrd.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 integer c__3 = 3;
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static integer c__2 = 2;
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static doublereal c_b21 = -1.;
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static doublereal c_b22 = 1.;
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/* > \brief \b DGEBRD */
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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 DGEBRD + dependencies */
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/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dgebrd.
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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/dgebrd.
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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/dgebrd.
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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 DGEBRD( M, N, A, LDA, D, E, TAUQ, TAUP, WORK, LWORK, */
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/* INFO ) */
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/* .. Scalar Arguments .. */
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/* INTEGER INFO, LDA, LWORK, M, N */
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/* .. */
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/* .. Array Arguments .. */
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/* DOUBLE PRECISION A( LDA, * ), D( * ), E( * ), TAUP( * ), */
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/* $ TAUQ( * ), 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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/* > DGEBRD reduces a general real M-by-N matrix A to upper or lower */
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/* > bidiagonal form B by an orthogonal transformation: Q**T * A * P = B. */
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/* > */
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/* > If m >= n, B is upper bidiagonal; if m < n, B is lower bidiagonal. */
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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 in 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 in 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 general matrix to be reduced. */
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/* > On exit, */
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/* > if m >= n, the diagonal and the first superdiagonal are */
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/* > overwritten with the upper bidiagonal matrix B; the */
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/* > elements below the diagonal, with the array TAUQ, represent */
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/* > the orthogonal matrix Q as a product of elementary */
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/* > reflectors, and the elements above the first superdiagonal, */
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/* > with the array TAUP, represent the orthogonal matrix P as */
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/* > a product of elementary reflectors; */
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/* > if m < n, the diagonal and the first subdiagonal are */
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/* > overwritten with the lower bidiagonal matrix B; the */
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/* > elements below the first subdiagonal, with the array TAUQ, */
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/* > represent the orthogonal matrix Q as a product of */
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/* > elementary reflectors, and the elements above the diagonal, */
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/* > with the array TAUP, represent the orthogonal matrix P as */
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/* > a product of elementary reflectors. */
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/* > See Further Details. */
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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] D */
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/* > \verbatim */
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/* > D is DOUBLE PRECISION array, dimension (min(M,N)) */
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/* > The diagonal elements of the bidiagonal matrix B: */
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/* > D(i) = A(i,i). */
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/* > \endverbatim */
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/* > */
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/* > \param[out] E */
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/* > \verbatim */
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/* > E is DOUBLE PRECISION array, dimension (min(M,N)-1) */
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/* > The off-diagonal elements of the bidiagonal matrix B: */
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/* > if m >= n, E(i) = A(i,i+1) for i = 1,2,...,n-1; */
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/* > if m < n, E(i) = A(i+1,i) for i = 1,2,...,m-1. */
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/* > \endverbatim */
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/* > */
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/* > \param[out] TAUQ */
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/* > \verbatim */
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/* > TAUQ is DOUBLE PRECISION array, dimension (min(M,N)) */
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/* > The scalar factors of the elementary reflectors which */
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/* > represent the orthogonal matrix Q. See Further Details. */
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/* > \endverbatim */
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/* > */
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/* > \param[out] TAUP */
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/* > \verbatim */
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/* > TAUP is DOUBLE PRECISION array, dimension (min(M,N)) */
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/* > The scalar factors of the elementary reflectors which */
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/* > represent the orthogonal matrix P. See Further Details. */
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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 length of the array WORK. LWORK >= max(1,M,N). */
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/* > For optimum performance LWORK >= (M+N)*NB, where NB */
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/* > is 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 doubleGEcomputational */
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/* > \par Further Details: */
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/* ===================== */
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/* > */
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/* > \verbatim */
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/* > */
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/* > The matrices Q and P are represented as products of elementary */
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/* > reflectors: */
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/* > */
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/* > If m >= n, */
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/* > */
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/* > Q = H(1) H(2) . . . H(n) and P = G(1) G(2) . . . G(n-1) */
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/* > */
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/* > Each H(i) and G(i) has the form: */
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/* > */
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/* > H(i) = I - tauq * v * v**T and G(i) = I - taup * u * u**T */
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/* > */
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/* > where tauq and taup are real scalars, and v and u are real vectors; */
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/* > v(1:i-1) = 0, v(i) = 1, and v(i+1:m) is stored on exit in A(i+1:m,i); */
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/* > u(1:i) = 0, u(i+1) = 1, and u(i+2:n) is stored on exit in A(i,i+2:n); */
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/* > tauq is stored in TAUQ(i) and taup in TAUP(i). */
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/* > */
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/* > If m < n, */
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/* > */
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/* > Q = H(1) H(2) . . . H(m-1) and P = G(1) G(2) . . . G(m) */
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/* > */
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/* > Each H(i) and G(i) has the form: */
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/* > */
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/* > H(i) = I - tauq * v * v**T and G(i) = I - taup * u * u**T */
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/* > */
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/* > where tauq and taup are real scalars, and v and u are real vectors; */
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/* > v(1:i) = 0, v(i+1) = 1, and v(i+2:m) is stored on exit in A(i+2:m,i); */
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/* > u(1:i-1) = 0, u(i) = 1, and u(i+1:n) is stored on exit in A(i,i+1:n); */
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/* > tauq is stored in TAUQ(i) and taup in TAUP(i). */
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/* > */
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/* > The contents of A on exit are illustrated by the following examples: */
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/* > */
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/* > m = 6 and n = 5 (m > n): m = 5 and n = 6 (m < n): */
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/* > */
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/* > ( d e u1 u1 u1 ) ( d u1 u1 u1 u1 u1 ) */
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/* > ( v1 d e u2 u2 ) ( e d u2 u2 u2 u2 ) */
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/* > ( v1 v2 d e u3 ) ( v1 e d u3 u3 u3 ) */
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/* > ( v1 v2 v3 d e ) ( v1 v2 e d u4 u4 ) */
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/* > ( v1 v2 v3 v4 d ) ( v1 v2 v3 e d u5 ) */
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/* > ( v1 v2 v3 v4 v5 ) */
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/* > */
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/* > where d and e denote diagonal and off-diagonal elements of B, vi */
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/* > denotes an element of the vector defining H(i), and ui an element of */
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/* > the vector defining G(i). */
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/* > \endverbatim */
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/* > */
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/* ===================================================================== */
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/* Subroutine */ int dgebrd_(integer *m, integer *n, doublereal *a, integer *
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lda, doublereal *d__, doublereal *e, doublereal *tauq, doublereal *
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taup, doublereal *work, integer *lwork, 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;
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/* Local variables */
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integer i__, j, nb, nx, ws;
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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 nbmin, iinfo, minmn;
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extern /* Subroutine */ int dgebd2_(integer *, integer *, doublereal *,
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integer *, doublereal *, doublereal *, doublereal *, doublereal *,
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doublereal *, integer *), dlabrd_(integer *, integer *, integer *
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, doublereal *, integer *, doublereal *, doublereal *, doublereal
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*, doublereal *, doublereal *, integer *, doublereal *, integer *)
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, 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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integer ldwrkx, ldwrky, 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 Subroutines .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. External 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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--d__;
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--e;
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--tauq;
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--taup;
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--work;
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/* Function Body */
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*info = 0;
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/* Computing MAX */
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i__1 = 1, i__2 = ilaenv_(&c__1, (char *)"DGEBRD", (char *)" ", m, n, &c_n1, &c_n1, (
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ftnlen)6, (ftnlen)1);
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nb = max(i__1,i__2);
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lwkopt = (*m + *n) * nb;
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work[1] = (doublereal) lwkopt;
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lquery = *lwork == -1;
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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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} else /* if(complicated condition) */ {
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/* Computing MAX */
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i__1 = max(1,*m);
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if (*lwork < max(i__1,*n) && ! lquery) {
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*info = -10;
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}
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}
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if (*info < 0) {
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i__1 = -(*info);
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xerbla_((char *)"DGEBRD", &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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minmn = min(*m,*n);
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if (minmn == 0) {
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work[1] = 1.;
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return 0;
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}
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ws = max(*m,*n);
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ldwrkx = *m;
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ldwrky = *n;
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if (nb > 1 && nb < minmn) {
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/* Set the crossover point NX. */
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/* Computing MAX */
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i__1 = nb, i__2 = ilaenv_(&c__3, (char *)"DGEBRD", (char *)" ", m, n, &c_n1, &c_n1, (
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ftnlen)6, (ftnlen)1);
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nx = max(i__1,i__2);
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/* Determine when to switch from blocked to unblocked code. */
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if (nx < minmn) {
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ws = (*m + *n) * nb;
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if (*lwork < ws) {
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/* Not enough work space for the optimal NB, consider using */
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/* a smaller block size. */
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nbmin = ilaenv_(&c__2, (char *)"DGEBRD", (char *)" ", m, n, &c_n1, &c_n1, (
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ftnlen)6, (ftnlen)1);
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if (*lwork >= (*m + *n) * nbmin) {
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nb = *lwork / (*m + *n);
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||||
} else {
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nb = 1;
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||||
nx = minmn;
|
||||
}
|
||||
}
|
||||
}
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} else {
|
||||
nx = minmn;
|
||||
}
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||||
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i__1 = minmn - nx;
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||||
i__2 = nb;
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for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
|
||||
|
||||
/* Reduce rows and columns i:i+nb-1 to bidiagonal form and return */
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||||
/* the matrices X and Y which are needed to update the unreduced */
|
||||
/* part of the matrix */
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||||
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||||
i__3 = *m - i__ + 1;
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i__4 = *n - i__ + 1;
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dlabrd_(&i__3, &i__4, &nb, &a[i__ + i__ * a_dim1], lda, &d__[i__], &e[
|
||||
i__], &tauq[i__], &taup[i__], &work[1], &ldwrkx, &work[ldwrkx
|
||||
* nb + 1], &ldwrky);
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||||
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/* Update the trailing submatrix A(i+nb:m,i+nb:n), using an update */
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||||
/* of the form A := A - V*Y**T - X*U**T */
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||||
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i__3 = *m - i__ - nb + 1;
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||||
i__4 = *n - i__ - nb + 1;
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dgemm_((char *)"No transpose", (char *)"Transpose", &i__3, &i__4, &nb, &c_b21, &a[i__
|
||||
+ nb + i__ * a_dim1], lda, &work[ldwrkx * nb + nb + 1], &
|
||||
ldwrky, &c_b22, &a[i__ + nb + (i__ + nb) * a_dim1], lda, (
|
||||
ftnlen)12, (ftnlen)9);
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||||
i__3 = *m - i__ - nb + 1;
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||||
i__4 = *n - i__ - nb + 1;
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||||
dgemm_((char *)"No transpose", (char *)"No transpose", &i__3, &i__4, &nb, &c_b21, &
|
||||
work[nb + 1], &ldwrkx, &a[i__ + (i__ + nb) * a_dim1], lda, &
|
||||
c_b22, &a[i__ + nb + (i__ + nb) * a_dim1], lda, (ftnlen)12, (
|
||||
ftnlen)12);
|
||||
|
||||
/* Copy diagonal and off-diagonal elements of B back into A */
|
||||
|
||||
if (*m >= *n) {
|
||||
i__3 = i__ + nb - 1;
|
||||
for (j = i__; j <= i__3; ++j) {
|
||||
a[j + j * a_dim1] = d__[j];
|
||||
a[j + (j + 1) * a_dim1] = e[j];
|
||||
/* L10: */
|
||||
}
|
||||
} else {
|
||||
i__3 = i__ + nb - 1;
|
||||
for (j = i__; j <= i__3; ++j) {
|
||||
a[j + j * a_dim1] = d__[j];
|
||||
a[j + 1 + j * a_dim1] = e[j];
|
||||
/* L20: */
|
||||
}
|
||||
}
|
||||
/* L30: */
|
||||
}
|
||||
|
||||
/* Use unblocked code to reduce the remainder of the matrix */
|
||||
|
||||
i__2 = *m - i__ + 1;
|
||||
i__1 = *n - i__ + 1;
|
||||
dgebd2_(&i__2, &i__1, &a[i__ + i__ * a_dim1], lda, &d__[i__], &e[i__], &
|
||||
tauq[i__], &taup[i__], &work[1], &iinfo);
|
||||
work[1] = (doublereal) ws;
|
||||
return 0;
|
||||
|
||||
/* End of DGEBRD */
|
||||
|
||||
} /* dgebrd_ */
|
||||
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
Reference in New Issue
Block a user