294 lines
8.6 KiB
C
294 lines
8.6 KiB
C
/* -- translated by f2c (version 20240504).
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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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#include "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_b13 = -1.;
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static doublereal c_b14 = 1.;
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/* > \brief \b DPOTRF
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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 DPOTRF + dependencies
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> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dpotrf.
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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/dpotrf.
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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/dpotrf.
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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 DPOTRF( UPLO, N, A, LDA, INFO )
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CHARACTER UPLO
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INTEGER INFO, LDA, N
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DOUBLE PRECISION A( LDA, * )
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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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> DPOTRF computes the Cholesky factorization of a real symmetric
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> positive definite matrix A.
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>
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> The factorization has the form
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> A = U**T * U, if UPLO = 'U', or
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> A = L * L**T, if UPLO = 'L',
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> where U is an upper triangular matrix and L is lower triangular.
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>
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> This is the block version of the algorithm, calling Level 3 BLAS.
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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 is stored;
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> = 'L': Lower triangle of A is stored.
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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,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 symmetric matrix A. If UPLO = 'U', the leading
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> N-by-N upper triangular part of A contains the upper
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> triangular part of the matrix A, and the strictly lower
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> triangular part of A is not referenced. If UPLO = 'L', the
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> leading N-by-N lower triangular part of A contains the lower
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> triangular part of the matrix A, and the strictly upper
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> triangular part of A is not referenced.
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>
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> On exit, if INFO = 0, the factor U or L from the Cholesky
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> factorization A = U**T*U or A = L*L**T.
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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[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, the leading minor of order i is not
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> positive definite, and the factorization could not be
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> completed.
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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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> \date November 2011
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> \ingroup doublePOcomputational
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=====================================================================
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Subroutine */ int igraphdpotrf_(char *uplo, integer *n, doublereal *a, integer *
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lda, 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 j, jb, nb;
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extern /* Subroutine */ int igraphdgemm_(char *, char *, integer *, integer *,
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integer *, doublereal *, doublereal *, integer *, doublereal *,
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integer *, doublereal *, doublereal *, integer *);
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extern logical igraphlsame_(char *, char *);
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extern /* Subroutine */ int igraphdtrsm_(char *, char *, char *, char *,
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integer *, integer *, doublereal *, doublereal *, integer *,
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doublereal *, integer *);
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logical upper;
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extern /* Subroutine */ int igraphdsyrk_(char *, char *, integer *, integer *,
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doublereal *, doublereal *, integer *, doublereal *, doublereal *,
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integer *), igraphdpotf2_(char *, integer *,
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doublereal *, integer *, integer *), igraphxerbla_(char *,
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integer *, ftnlen);
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extern integer igraphilaenv_(integer *, char *, char *, integer *, integer *,
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integer *, integer *, ftnlen, ftnlen);
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/* -- LAPACK computational routine (version 3.4.0) --
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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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November 2011
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=====================================================================
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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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/* Function Body */
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*info = 0;
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upper = igraphlsame_(uplo, "U");
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if (! upper && ! igraphlsame_(uplo, "L")) {
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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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}
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if (*info != 0) {
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i__1 = -(*info);
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igraphxerbla_("DPOTRF", &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) {
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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 = igraphilaenv_(&c__1, "DPOTRF", uplo, n, &c_n1, &c_n1, &c_n1, (ftnlen)6, (
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ftnlen)1);
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if (nb <= 1 || nb >= *n) {
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/* Use unblocked code. */
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igraphdpotf2_(uplo, n, &a[a_offset], lda, info);
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} else {
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/* Use blocked code. */
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if (upper) {
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/* Compute the Cholesky factorization A = U**T*U. */
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i__1 = *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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/* Update and factorize the current diagonal block and test
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for non-positive-definiteness.
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Computing MIN */
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i__3 = nb, i__4 = *n - j + 1;
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jb = min(i__3,i__4);
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i__3 = j - 1;
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igraphdsyrk_("Upper", "Transpose", &jb, &i__3, &c_b13, &a[j *
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a_dim1 + 1], lda, &c_b14, &a[j + j * a_dim1], lda);
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igraphdpotf2_("Upper", &jb, &a[j + j * a_dim1], lda, info);
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if (*info != 0) {
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goto L30;
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}
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if (j + jb <= *n) {
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/* Compute the current block row. */
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i__3 = *n - j - jb + 1;
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i__4 = j - 1;
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igraphdgemm_("Transpose", "No transpose", &jb, &i__3, &i__4, &
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c_b13, &a[j * a_dim1 + 1], lda, &a[(j + jb) *
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a_dim1 + 1], lda, &c_b14, &a[j + (j + jb) *
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a_dim1], lda);
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i__3 = *n - j - jb + 1;
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igraphdtrsm_("Left", "Upper", "Transpose", "Non-unit", &jb, &
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i__3, &c_b14, &a[j + j * a_dim1], lda, &a[j + (j
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+ jb) * a_dim1], lda);
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}
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/* L10: */
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}
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} else {
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/* Compute the Cholesky factorization A = L*L**T. */
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i__2 = *n;
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i__1 = nb;
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for (j = 1; i__1 < 0 ? j >= i__2 : j <= i__2; j += i__1) {
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/* Update and factorize the current diagonal block and test
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for non-positive-definiteness.
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Computing MIN */
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i__3 = nb, i__4 = *n - j + 1;
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jb = min(i__3,i__4);
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i__3 = j - 1;
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igraphdsyrk_("Lower", "No transpose", &jb, &i__3, &c_b13, &a[j +
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a_dim1], lda, &c_b14, &a[j + j * a_dim1], lda);
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igraphdpotf2_("Lower", &jb, &a[j + j * a_dim1], lda, info);
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if (*info != 0) {
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goto L30;
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}
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if (j + jb <= *n) {
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/* Compute the current block column. */
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i__3 = *n - j - jb + 1;
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i__4 = j - 1;
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igraphdgemm_("No transpose", "Transpose", &i__3, &jb, &i__4, &
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c_b13, &a[j + jb + a_dim1], lda, &a[j + a_dim1],
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lda, &c_b14, &a[j + jb + j * a_dim1], lda);
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i__3 = *n - j - jb + 1;
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igraphdtrsm_("Right", "Lower", "Transpose", "Non-unit", &i__3, &
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jb, &c_b14, &a[j + j * a_dim1], lda, &a[j + jb +
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j * a_dim1], lda);
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}
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/* L20: */
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}
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}
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}
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goto L40;
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L30:
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*info = *info + j - 1;
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L40:
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return 0;
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/* End of DPOTRF */
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} /* igraphdpotrf_ */
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