SRC/zgetf2.f(3) | Library Functions Manual | SRC/zgetf2.f(3) |
NAME
SRC/zgetf2.f
SYNOPSIS
Functions/Subroutines
subroutine zgetf2 (m, n, a, lda, ipiv, info)
ZGETF2 computes the LU factorization of a general m-by-n matrix using
partial pivoting with row interchanges (unblocked algorithm).
Function/Subroutine Documentation
subroutine zgetf2 (integer m, integer n, complex*16, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, integer info)
ZGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).
Purpose:
!> !> ZGETF2 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 COMPLEX*16 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 zgetf2.f.
Author
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