218 lines
6.1 KiB
C
218 lines
6.1 KiB
C
/* sgetrf.f -- translated by f2c (version 20061008).
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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 "clapack.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 real c_b16 = 1.f;
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static real c_b19 = -1.f;
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/* Subroutine */ int sgetrf_(integer *m, integer *n, real *a, integer *lda,
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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, iinfo;
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extern /* Subroutine */ int sgemm_(char *, char *, integer *, integer *,
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integer *, real *, real *, integer *, real *, integer *, real *,
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real *, integer *), strsm_(char *, char *, char *,
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char *, integer *, integer *, real *, real *, integer *, real *,
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integer *), sgetf2_(integer *,
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integer *, real *, integer *, integer *, integer *), xerbla_(char
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*, integer *);
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extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
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integer *, integer *);
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extern /* Subroutine */ int slaswp_(integer *, real *, integer *, integer
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*, integer *, integer *, integer *);
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/* -- LAPACK routine (version 3.2) -- */
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/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
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/* November 2006 */
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* SGETRF 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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/* 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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/* This is the right-looking Level 3 BLAS version of the algorithm. */
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/* Arguments */
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/* ========= */
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/* M (input) INTEGER */
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/* The number of rows of the matrix A. M >= 0. */
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/* N (input) INTEGER */
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/* The number of columns of the matrix A. N >= 0. */
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/* A (input/output) REAL 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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/* LDA (input) INTEGER */
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/* The leading dimension of the array A. LDA >= max(1,M). */
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/* IPIV (output) 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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/* INFO (output) 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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/* ===================================================================== */
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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_("SGETRF", &i__1);
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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, "SGETRF", " ", m, n, &c_n1, &c_n1);
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if (nb <= 1 || nb >= min(*m,*n)) {
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/* Use unblocked code. */
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sgetf2_(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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sgetf2_(&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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slaswp_(&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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slaswp_(&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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strsm_("Left", "Lower", "No transpose", "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);
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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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sgemm_("No transpose", "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);
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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 SGETRF */
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} /* sgetrf_ */
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