zgetri (l)  Linux Manuals
zgetri: computes the inverse of a matrix using the LU factorization computed by ZGETRF
Command to display zgetri
manual in Linux: $ man l zgetri
NAME
ZGETRI  computes the inverse of a matrix using the LU factorization computed by ZGETRF
SYNOPSIS
 SUBROUTINE ZGETRI(

N, A, LDA, IPIV, WORK, LWORK, INFO )

INTEGER
INFO, LDA, LWORK, N

INTEGER
IPIV( * )

COMPLEX*16
A( LDA, * ), WORK( * )
PURPOSE
ZGETRI computes the inverse of a matrix using the LU factorization
computed by ZGETRF.
This method inverts U and then computes inv(A) by solving the system
inv(A)*L = inv(U) for inv(A).
ARGUMENTS
 N (input) INTEGER

The order of the matrix A. N >= 0.
 A (input/output) COMPLEX*16 array, dimension (LDA,N)

On entry, the factors L and U from the factorization
A = P*L*U as computed by ZGETRF.
On exit, if INFO = 0, the inverse of the original matrix A.
 LDA (input) INTEGER

The leading dimension of the array A. LDA >= max(1,N).
 IPIV (input) INTEGER array, dimension (N)

The pivot indices from ZGETRF; for 1<=i<=N, row i of the
matrix was interchanged with row IPIV(i).
 WORK (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK))

On exit, if INFO=0, then WORK(1) returns the optimal LWORK.
 LWORK (input) INTEGER

The dimension of the array WORK. LWORK >= max(1,N).
For optimal performance LWORK >= N*NB, where NB is
the optimal blocksize returned by ILAENV.
If LWORK = 1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
> 0: if INFO = i, U(i,i) is exactly zero; the matrix is
singular and its inverse could not be computed.
Pages related to zgetri
 zgetri (3)
 zgetrf (l)  computes an LU factorization of a general MbyN matrix A using partial pivoting with row interchanges
 zgetrs (l)  solves a system of linear equations A * X = B, A**T * X = B, or A**H * X = B with a general NbyN matrix A using the LU factorization computed by ZGETRF
 zgetc2 (l)  computes an LU factorization, using complete pivoting, of the nbyn matrix A
 zgetf2 (l)  computes an LU factorization of a general mbyn matrix A using partial pivoting with row interchanges
 zgebak (l)  forms the right or left eigenvectors of a complex general matrix by backward transformation on the computed eigenvectors of the balanced matrix output by ZGEBAL
 zgebal (l)  balances a general complex matrix A
 zgebd2 (l)  reduces a complex general m by n matrix A to upper or lower real bidiagonal form B by a unitary transformation