ZGETRI(l) ) ZGETRI(l)
ZGETRI - compute the inverse of a matrix using the LU factorization computed by ZGETRF
SUBROUTINE ZGETRI( N, A, LDA, IPIV, WORK, LWORK, INFO )
INTEGER INFO, LDA, LWORK, N
INTEGER IPIV( * )
COMPLEX*16 A( LDA, * ), WORK( * )
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
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 (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 i-th 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.
LAPACK version 3.0 15 June 2000 ZGETRI(l)