dgetri.f (3) Linux Manual Page
dgetri.f –
Synopsis
Functions/Subroutines
subroutine dgetri (N, A, LDA, IPIV, WORK, LWORK, INFO)DGETRI
Function/Subroutine Documentation
subroutine dgetri (integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, double precision, dimension( * )WORK, integerLWORK, integerINFO)
DGETRI Purpose:
DGETRI computes the inverse of a matrix using the LU factorization
computed by DGETRF.
This method inverts U and then computes inv(A) by solving the system
inv(A)*L = inv(U) for inv(A).
Parameters:
- N
N is INTEGER
A
The order of the matrix A. N >= 0.A is DOUBLE PRECISION array, dimension (LDA,N)
LDA
On entry, the factors L and U from the factorization
A = P*L*U as computed by DGETRF.
On exit, if INFO = 0, the inverse of the original matrix A.LDA is INTEGER
IPIV
The leading dimension of the array A. LDA >= max(1,N).IPIV is INTEGER array, dimension (N)
WORK
The pivot indices from DGETRF; for 1<=i<=N, row i of the
matrix was interchanged with row IPIV(i).WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
LWORK
On exit, if INFO=0, then WORK(1) returns the optimal LWORK.LWORK is INTEGER
INFO
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 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 matrix is
singular and its inverse could not be computed.
Author:
- Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
- November 2011
Definition at line 115 of file dgetri.f.