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NAME
     dgetrf - compute an LU factorization  of  a  general  M-by-N
     matrix A using partial pivoting with row interchanges

SYNOPSIS
     SUBROUTINE DGETRF( M, N, A, LDA, IPIV, INFO )

     INTEGER INFO, LDA, M, N

     INTEGER IPIV( * )

     DOUBLE PRECISION A( LDA, * )



     #include <sunperf.h>

     void dgetrf(int m, int n, double *da, int lda, int  *ipivot,
               int *info) ;

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  algo-
     rithm.


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 ille-
               gal 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 equa-
               tions.

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