comparison ext/clapack/src/dgetrf.c @ 430:335af74a25b6

Merge from branch clapack-included

+/* dgetrf.f -- translated by f2c (version 20061008).
+   You must link the resulting object file with libf2c:
+	on Microsoft Windows system, link with libf2c.lib;
+	on Linux or Unix systems, link with .../path/to/libf2c.a -lm
+	or, if you install libf2c.a in a standard place, with -lf2c -lm
+	-- in that order, at the end of the command line, as in
+		cc *.o -lf2c -lm
+	Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
+
+		http://www.netlib.org/f2c/libf2c.zip
+*/
+
+#include "f2c.h"
+#include "blaswrap.h"
+
+/* Table of constant values */
+
+static integer c__1 = 1;
+static integer c_n1 = -1;
+static doublereal c_b16 = 1.;
+static doublereal c_b19 = -1.;
+
+/* Subroutine */ int dgetrf_(integer *m, integer *n, doublereal *a, integer *
+	lda, integer *ipiv, integer *info)
+{
+    /* System generated locals */
+    integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5;
+
+    /* Local variables */
+    integer i__, j, jb, nb;
+    extern /* Subroutine */ int dgemm_(char *, char *, integer *, integer *, 
+	    integer *, doublereal *, doublereal *, integer *, doublereal *, 
+	    integer *, doublereal *, doublereal *, integer *);
+    integer iinfo;
+    extern /* Subroutine */ int dtrsm_(char *, char *, char *, char *, 
+	    integer *, integer *, doublereal *, doublereal *, integer *, 
+	    doublereal *, integer *), dgetf2_(
+	    integer *, integer *, doublereal *, integer *, integer *, integer 
+	    *), xerbla_(char *, integer *);
+    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 
+	    integer *, integer *);
+    extern /* Subroutine */ int dlaswp_(integer *, doublereal *, integer *, 
+	    integer *, integer *, integer *, integer *);
+
+
+/*  -- LAPACK routine (version 3.2) -- */
+/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/*     November 2006 */
+
+/*     .. Scalar Arguments .. */
+/*     .. */
+/*     .. Array Arguments .. */
+/*     .. */
+
+/*  Purpose */
+/*  ======= */
+
+/*  DGETRF computes an LU factorization of a general M-by-N matrix A */
+/*  using partial pivoting with row interchanges. */
+
+/*  The factorization has the form */
+/*     A = P * L * U */
+/*  where P is a permutation matrix, L is lower triangular with unit */
+/*  diagonal elements (lower trapezoidal if m > n), and U is upper */
+/*  triangular (upper trapezoidal if m < n). */
+
+/*  This is the right-looking Level 3 BLAS version of the algorithm. */
+
+/*  Arguments */
+/*  ========= */
+
+/*  M       (input) INTEGER */
+/*          The number of rows of the matrix A.  M >= 0. */
+
+/*  N       (input) INTEGER */
+/*          The number of columns of the matrix A.  N >= 0. */
+
+/*  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N) */
+/*          On entry, the M-by-N matrix to be factored. */
+/*          On exit, the factors L and U from the factorization */
+/*          A = P*L*U; the unit diagonal elements of L are not stored. */
+
+/*  LDA     (input) INTEGER */
+/*          The leading dimension of the array A.  LDA >= max(1,M). */
+
+/*  IPIV    (output) INTEGER array, dimension (min(M,N)) */
+/*          The pivot indices; for 1 <= i <= min(M,N), row i of the */
+/*          matrix was interchanged with row IPIV(i). */
+
+/*  INFO    (output) INTEGER */
+/*          = 0:  successful exit */
+/*          < 0:  if INFO = -i, the i-th argument had an illegal value */
+/*          > 0:  if INFO = i, U(i,i) is exactly zero. The factorization */
+/*                has been completed, but the factor U is exactly */
+/*                singular, and division by zero will occur if it is used */
+/*                to solve a system of equations. */
+
+/*  ===================================================================== */
+
+/*     .. Parameters .. */
+/*     .. */
+/*     .. Local Scalars .. */
+/*     .. */
+/*     .. External Subroutines .. */
+/*     .. */
+/*     .. External Functions .. */
+/*     .. */
+/*     .. Intrinsic Functions .. */
+/*     .. */
+/*     .. Executable Statements .. */
+
+/*     Test the input parameters. */
+
+    /* Parameter adjustments */
+    a_dim1 = *lda;
+    a_offset = 1 + a_dim1;
+    a -= a_offset;
+    --ipiv;
+
+    /* Function Body */
+    *info = 0;
+    if (*m < 0) {
+	*info = -1;
+    } else if (*n < 0) {
+	*info = -2;
+    } else if (*lda < max(1,*m)) {
+	*info = -4;
+    }
+    if (*info != 0) {
+	i__1 = -(*info);
+	xerbla_("DGETRF", &i__1);
+	return 0;
+    }
+
+/*     Quick return if possible */
+
+    if (*m == 0 || *n == 0) {
+	return 0;
+    }
+
+/*     Determine the block size for this environment. */
+
+    nb = ilaenv_(&c__1, "DGETRF", " ", m, n, &c_n1, &c_n1);
+    if (nb <= 1 || nb >= min(*m,*n)) {
+
+/*        Use unblocked code. */
+
+	dgetf2_(m, n, &a[a_offset], lda, &ipiv[1], info);
+    } else {
+
+/*        Use blocked code. */
+
+	i__1 = min(*m,*n);
+	i__2 = nb;
+	for (j = 1; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) {
+/* Computing MIN */
+	    i__3 = min(*m,*n) - j + 1;
+	    jb = min(i__3,nb);
+
+/*           Factor diagonal and subdiagonal blocks and test for exact */
+/*           singularity. */
+
+	    i__3 = *m - j + 1;
+	    dgetf2_(&i__3, &jb, &a[j + j * a_dim1], lda, &ipiv[j], &iinfo);
+
+/*           Adjust INFO and the pivot indices. */
+
+	    if (*info == 0 && iinfo > 0) {
+		*info = iinfo + j - 1;
+	    }
+/* Computing MIN */
+	    i__4 = *m, i__5 = j + jb - 1;
+	    i__3 = min(i__4,i__5);
+	    for (i__ = j; i__ <= i__3; ++i__) {
+		ipiv[i__] = j - 1 + ipiv[i__];
+/* L10: */
+	    }
+
+/*           Apply interchanges to columns 1:J-1. */
+
+	    i__3 = j - 1;
+	    i__4 = j + jb - 1;
+	    dlaswp_(&i__3, &a[a_offset], lda, &j, &i__4, &ipiv[1], &c__1);
+
+	    if (j + jb <= *n) {
+
+/*              Apply interchanges to columns J+JB:N. */
+
+		i__3 = *n - j - jb + 1;
+		i__4 = j + jb - 1;
+		dlaswp_(&i__3, &a[(j + jb) * a_dim1 + 1], lda, &j, &i__4, &
+			ipiv[1], &c__1);
+
+/*              Compute block row of U. */
+
+		i__3 = *n - j - jb + 1;
+		dtrsm_("Left", "Lower", "No transpose", "Unit", &jb, &i__3, &
+			c_b16, &a[j + j * a_dim1], lda, &a[j + (j + jb) * 
+			a_dim1], lda);
+		if (j + jb <= *m) {
+
+/*                 Update trailing submatrix. */
+
+		    i__3 = *m - j - jb + 1;
+		    i__4 = *n - j - jb + 1;
+		    dgemm_("No transpose", "No transpose", &i__3, &i__4, &jb, 
+			    &c_b19, &a[j + jb + j * a_dim1], lda, &a[j + (j + 
+			    jb) * a_dim1], lda, &c_b16, &a[j + jb + (j + jb) *
+			     a_dim1], lda);
+		}
+	    }
+/* L20: */
+	}
+    }
+    return 0;
+
+/*     End of DGETRF */
+
+} /* dgetrf_ */