ZGETRF(1) | LAPACK routine (version 3.2) | ZGETRF(1) |
NAME¶
ZGETRF - computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges
SYNOPSIS¶
- SUBROUTINE ZGETRF(
- M, N, A, LDA, IPIV, INFO )
INTEGER INFO, LDA, M, N INTEGER IPIV( * ) COMPLEX*16 A( LDA, * )
PURPOSE¶
ZGETRF 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 algorithm.
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) 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 = -i, the i-th argument had an illegal 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 equations.
November 2008 | LAPACK routine (version 3.2) |