LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  chetri2 (UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO) 
CHETRI2 
subroutine chetri2  (  character  UPLO, 
integer  N,  
complex, dimension( lda, * )  A,  
integer  LDA,  
integer, dimension( * )  IPIV,  
complex, dimension( * )  WORK,  
integer  LWORK,  
integer  INFO  
) 
CHETRI2
Download CHETRI2 + dependencies [TGZ] [ZIP] [TXT]CHETRI2 computes the inverse of a COMPLEX hermitian indefinite matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by CHETRF. CHETRI2 set the LEADING DIMENSION of the workspace before calling CHETRI2X that actually computes the inverse.
[in]  UPLO  UPLO is CHARACTER*1 Specifies whether the details of the factorization are stored as an upper or lower triangular matrix. = 'U': Upper triangular, form is A = U*D*U**T; = 'L': Lower triangular, form is A = L*D*L**T. 
[in]  N  N is INTEGER The order of the matrix A. N >= 0. 
[in,out]  A  A is COMPLEX array, dimension (LDA,N) On entry, the NB diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CHETRF. On exit, if INFO = 0, the (symmetric) inverse of the original matrix. If UPLO = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced; if UPLO = 'L' the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced. 
[in]  LDA  LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N). 
[in]  IPIV  IPIV is INTEGER array, dimension (N) Details of the interchanges and the NB structure of D as determined by CHETRF. 
[out]  WORK  WORK is COMPLEX array, dimension (N+NB+1)*(NB+3) 
[in]  LWORK  LWORK is INTEGER The dimension of the array WORK. WORK is size >= (N+NB+1)*(NB+3) If LDWORK = 1, then a workspace query is assumed; the routine 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. 
[out]  INFO  INFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its inverse could not be computed. 
Definition at line 128 of file chetri2.f.