cgetri(3P) Sun Performance Library cgetri(3P)NAMEcgetri - compute the inverse of a matrix using the LU factorization
computed by CGETRF
SYNOPSIS
SUBROUTINE CGETRI(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)
COMPLEX A(LDA,*), WORK(*)
INTEGER N, LDA, LDWORK, INFO
INTEGER IPIVOT(*)
SUBROUTINE CGETRI_64(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)
COMPLEX A(LDA,*), WORK(*)
INTEGER*8 N, LDA, LDWORK, INFO
INTEGER*8 IPIVOT(*)
F95 INTERFACE
SUBROUTINE GETRI([N], A, [LDA], IPIVOT, [WORK], [LDWORK], [INFO])
COMPLEX, DIMENSION(:) :: WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: N, LDA, LDWORK, INFO
INTEGER, DIMENSION(:) :: IPIVOT
SUBROUTINE GETRI_64([N], A, [LDA], IPIVOT, [WORK], [LDWORK], [INFO])
COMPLEX, DIMENSION(:) :: WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: N, LDA, LDWORK, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
C INTERFACE
#include <sunperf.h>
void cgetri(int n, complex *a, int lda, int *ipivot, int *info);
void cgetri_64(long n, complex *a, long lda, long *ipivot, long *info);
PURPOSEcgetri computes the inverse of a matrix using the LU factorization com‐
puted by CGETRF.
This method inverts U and then computes inv(A) by solving the system
inv(A)*L = inv(U) for inv(A).
ARGUMENTS
N (input) The order of the matrix A. N >= 0.
A (input/output)
On entry, the factors L and U from the factorization A =
P*L*U as computed by CGETRF. On exit, if INFO = 0, the
inverse of the original matrix A.
LDA (input)
The leading dimension of the array A. LDA >= max(1,N).
IPIVOT (input)
The pivot indices from CGETRF; for 1<=i<=N, row i of the
matrix was interchanged with row IPIVOT(i).
WORK (workspace)
On exit, if INFO=0, then WORK(1) returns the optimal LDWORK.
LDWORK (input)
The dimension of the array WORK. LDWORK >= max(1,N). For
optimal performance LDWORK >= N*NB, where NB is the optimal
blocksize returned by ILAENV.
If LDWORK = -1, then a workspace query is assumed; the rou‐
tine 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 LDWORK is issued by XERBLA.
INFO (output)
= 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 sin‐
gular and its inverse could not be computed.
6 Mar 2009 cgetri(3P)