sgetf2.f(3)

NAME
sgetf2.f

SYNOPSIS

  Functions/Subroutines
subroutine sgetf2 (M, N, A, LDA, IPIV, INFO)
SGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

Function/Subroutine Documentation

  subroutine sgetf2 (integer M, integer N, real, dimension( lda, * ) A, integer LDA, integer, dimension( * ) IPIV, integer INFO)

Purpose:

     SGETF2 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 2 BLAS version of the algorithm.

Parameters
    M

              M is INTEGER
              The number of rows of the matrix A.  M >= 0.

    N

              N is INTEGER
              The number of columns of the matrix A.  N >= 0.

    A

              A is REAL 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

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,M).

    IPIV

              IPIV is 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

              INFO is INTEGER
              = 0: successful exit
              < 0: if INFO = -k, the k-th argument had an illegal value
              > 0: if INFO = k, U(k,k) 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.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 107 of file sgetf2.f.

Author

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