c@427: /* dgetf2.f -- translated by f2c (version 20061008).
c@427:    You must link the resulting object file with libf2c:
c@427: 	on Microsoft Windows system, link with libf2c.lib;
c@427: 	on Linux or Unix systems, link with .../path/to/libf2c.a -lm
c@427: 	or, if you install libf2c.a in a standard place, with -lf2c -lm
c@427: 	-- in that order, at the end of the command line, as in
c@427: 		cc *.o -lf2c -lm
c@427: 	Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
c@427: 
c@427: 		http://www.netlib.org/f2c/libf2c.zip
c@427: */
c@427: 
c@427: #include "f2c.h"
c@427: #include "blaswrap.h"
c@427: 
c@427: /* Table of constant values */
c@427: 
c@427: static integer c__1 = 1;
c@427: static doublereal c_b8 = -1.;
c@427: 
c@427: /* Subroutine */ int dgetf2_(integer *m, integer *n, doublereal *a, integer *
c@427: 	lda, integer *ipiv, integer *info)
c@427: {
c@427:     /* System generated locals */
c@427:     integer a_dim1, a_offset, i__1, i__2, i__3;
c@427:     doublereal d__1;
c@427: 
c@427:     /* Local variables */
c@427:     integer i__, j, jp;
c@427:     extern /* Subroutine */ int dger_(integer *, integer *, doublereal *, 
c@427: 	    doublereal *, integer *, doublereal *, integer *, doublereal *, 
c@427: 	    integer *), dscal_(integer *, doublereal *, doublereal *, integer 
c@427: 	    *);
c@427:     doublereal sfmin;
c@427:     extern /* Subroutine */ int dswap_(integer *, doublereal *, integer *, 
c@427: 	    doublereal *, integer *);
c@427:     extern doublereal dlamch_(char *);
c@427:     extern integer idamax_(integer *, doublereal *, integer *);
c@427:     extern /* Subroutine */ int xerbla_(char *, integer *);
c@427: 
c@427: 
c@427: /*  -- LAPACK routine (version 3.2) -- */
c@427: /*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
c@427: /*     November 2006 */
c@427: 
c@427: /*     .. Scalar Arguments .. */
c@427: /*     .. */
c@427: /*     .. Array Arguments .. */
c@427: /*     .. */
c@427: 
c@427: /*  Purpose */
c@427: /*  ======= */
c@427: 
c@427: /*  DGETF2 computes an LU factorization of a general m-by-n matrix A */
c@427: /*  using partial pivoting with row interchanges. */
c@427: 
c@427: /*  The factorization has the form */
c@427: /*     A = P * L * U */
c@427: /*  where P is a permutation matrix, L is lower triangular with unit */
c@427: /*  diagonal elements (lower trapezoidal if m > n), and U is upper */
c@427: /*  triangular (upper trapezoidal if m < n). */
c@427: 
c@427: /*  This is the right-looking Level 2 BLAS version of the algorithm. */
c@427: 
c@427: /*  Arguments */
c@427: /*  ========= */
c@427: 
c@427: /*  M       (input) INTEGER */
c@427: /*          The number of rows of the matrix A.  M >= 0. */
c@427: 
c@427: /*  N       (input) INTEGER */
c@427: /*          The number of columns of the matrix A.  N >= 0. */
c@427: 
c@427: /*  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N) */
c@427: /*          On entry, the m by n matrix to be factored. */
c@427: /*          On exit, the factors L and U from the factorization */
c@427: /*          A = P*L*U; the unit diagonal elements of L are not stored. */
c@427: 
c@427: /*  LDA     (input) INTEGER */
c@427: /*          The leading dimension of the array A.  LDA >= max(1,M). */
c@427: 
c@427: /*  IPIV    (output) INTEGER array, dimension (min(M,N)) */
c@427: /*          The pivot indices; for 1 <= i <= min(M,N), row i of the */
c@427: /*          matrix was interchanged with row IPIV(i). */
c@427: 
c@427: /*  INFO    (output) INTEGER */
c@427: /*          = 0: successful exit */
c@427: /*          < 0: if INFO = -k, the k-th argument had an illegal value */
c@427: /*          > 0: if INFO = k, U(k,k) is exactly zero. The factorization */
c@427: /*               has been completed, but the factor U is exactly */
c@427: /*               singular, and division by zero will occur if it is used */
c@427: /*               to solve a system of equations. */
c@427: 
c@427: /*  ===================================================================== */
c@427: 
c@427: /*     .. Parameters .. */
c@427: /*     .. */
c@427: /*     .. Local Scalars .. */
c@427: /*     .. */
c@427: /*     .. External Functions .. */
c@427: /*     .. */
c@427: /*     .. External Subroutines .. */
c@427: /*     .. */
c@427: /*     .. Intrinsic Functions .. */
c@427: /*     .. */
c@427: /*     .. Executable Statements .. */
c@427: 
c@427: /*     Test the input parameters. */
c@427: 
c@427:     /* Parameter adjustments */
c@427:     a_dim1 = *lda;
c@427:     a_offset = 1 + a_dim1;
c@427:     a -= a_offset;
c@427:     --ipiv;
c@427: 
c@427:     /* Function Body */
c@427:     *info = 0;
c@427:     if (*m < 0) {
c@427: 	*info = -1;
c@427:     } else if (*n < 0) {
c@427: 	*info = -2;
c@427:     } else if (*lda < max(1,*m)) {
c@427: 	*info = -4;
c@427:     }
c@427:     if (*info != 0) {
c@427: 	i__1 = -(*info);
c@427: 	xerbla_("DGETF2", &i__1);
c@427: 	return 0;
c@427:     }
c@427: 
c@427: /*     Quick return if possible */
c@427: 
c@427:     if (*m == 0 || *n == 0) {
c@427: 	return 0;
c@427:     }
c@427: 
c@427: /*     Compute machine safe minimum */
c@427: 
c@427:     sfmin = dlamch_("S");
c@427: 
c@427:     i__1 = min(*m,*n);
c@427:     for (j = 1; j <= i__1; ++j) {
c@427: 
c@427: /*        Find pivot and test for singularity. */
c@427: 
c@427: 	i__2 = *m - j + 1;
c@427: 	jp = j - 1 + idamax_(&i__2, &a[j + j * a_dim1], &c__1);
c@427: 	ipiv[j] = jp;
c@427: 	if (a[jp + j * a_dim1] != 0.) {
c@427: 
c@427: /*           Apply the interchange to columns 1:N. */
c@427: 
c@427: 	    if (jp != j) {
c@427: 		dswap_(n, &a[j + a_dim1], lda, &a[jp + a_dim1], lda);
c@427: 	    }
c@427: 
c@427: /*           Compute elements J+1:M of J-th column. */
c@427: 
c@427: 	    if (j < *m) {
c@427: 		if ((d__1 = a[j + j * a_dim1], abs(d__1)) >= sfmin) {
c@427: 		    i__2 = *m - j;
c@427: 		    d__1 = 1. / a[j + j * a_dim1];
c@427: 		    dscal_(&i__2, &d__1, &a[j + 1 + j * a_dim1], &c__1);
c@427: 		} else {
c@427: 		    i__2 = *m - j;
c@427: 		    for (i__ = 1; i__ <= i__2; ++i__) {
c@427: 			a[j + i__ + j * a_dim1] /= a[j + j * a_dim1];
c@427: /* L20: */
c@427: 		    }
c@427: 		}
c@427: 	    }
c@427: 
c@427: 	} else if (*info == 0) {
c@427: 
c@427: 	    *info = j;
c@427: 	}
c@427: 
c@427: 	if (j < min(*m,*n)) {
c@427: 
c@427: /*           Update trailing submatrix. */
c@427: 
c@427: 	    i__2 = *m - j;
c@427: 	    i__3 = *n - j;
c@427: 	    dger_(&i__2, &i__3, &c_b8, &a[j + 1 + j * a_dim1], &c__1, &a[j + (
c@427: 		    j + 1) * a_dim1], lda, &a[j + 1 + (j + 1) * a_dim1], lda);
c@427: 	}
c@427: /* L10: */
c@427:     }
c@427:     return 0;
c@427: 
c@427: /*     End of DGETF2 */
c@427: 
c@427: } /* dgetf2_ */