GNU/Linux |
CentOS 4.8 |
i386 |
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zgetf2(l) |
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ZGETF2 - compute an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges
SUBROUTINE ZGETF2( |
M, N, A, LDA, IPIV, INFO ) |
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INTEGER |
INFO, LDA, M, N |
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INTEGER |
IPIV( * ) |
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COMPLEX*16 |
A( LDA, * ) |
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.
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) 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 (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 = -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.
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zgetf2(l) | ![]() |