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cgetrf.f(3) LAPACK cgetrf.f(3)

NAME

cgetrf.f

SYNOPSIS

Functions/Subroutines


subroutine cgetrf (M, N, A, LDA, IPIV, INFO)
CGETRF VARIANT: left-looking Level 3 BLAS version of the algorithm.

Function/Subroutine Documentation

subroutine cgetrf (integer M, integer N, complex, dimension( lda, * ) A, integer LDA, integer, dimension( * ) IPIV, integer INFO)

CGETRF VARIANT: left-looking Level 3 BLAS version of the algorithm. Purpose:


CGETRF 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 left-looking Level 3 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 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 = -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.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 102 of file VARIANTS/lu/LL/cgetrf.f.

Author

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Tue Nov 14 2017 Version 3.8.0