1DGETF2(1)                LAPACK routine (version 3.2)                DGETF2(1)
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NAME

6       DGETF2  -  computes  an  LU  factorization of a general m-by-n matrix A
7       using partial pivoting with row interchanges
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SYNOPSIS

10       SUBROUTINE DGETF2( M, N, A, LDA, IPIV, INFO )
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12           INTEGER        INFO, LDA, M, N
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14           INTEGER        IPIV( * )
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16           DOUBLE         PRECISION A( LDA, * )
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PURPOSE

19       DGETF2 computes an LU factorization of a general m-by-n matrix A  using
20       partial pivoting with row interchanges.  The factorization has the form
21          A = P * L * U
22       where P is a permutation matrix, L is lower triangular with unit diago‐
23       nal elements (lower trapezoidal if m > n), and U  is  upper  triangular
24       (upper trapezoidal if m < n).
25       This is the right-looking Level 2 BLAS version of the algorithm.
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ARGUMENTS

28       M       (input) INTEGER
29               The number of rows of the matrix A.  M >= 0.
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31       N       (input) INTEGER
32               The number of columns of the matrix A.  N >= 0.
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34       A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
35               On  entry, the m by n matrix to be factored.  On exit, the fac‐
36               tors L and U from the factorization A = P*L*U; the unit  diago‐
37               nal elements of L are not stored.
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39       LDA     (input) INTEGER
40               The leading dimension of the array A.  LDA >= max(1,M).
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42       IPIV    (output) INTEGER array, dimension (min(M,N))
43               The  pivot indices; for 1 <= i <= min(M,N), row i of the matrix
44               was interchanged with row IPIV(i).
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46       INFO    (output) INTEGER
47               = 0: successful exit
48               < 0: if INFO = -k, the k-th argument had an illegal value
49               > 0: if INFO = k, U(k,k) is exactly zero. The factorization has
50               been completed, but the factor U is exactly singular, and divi‐
51               sion by zero will occur if it is used  to  solve  a  system  of
52               equations.
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56 LAPACK routine (version 3.2)    November 2008                       DGETF2(1)
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