LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  chptri (UPLO, N, AP, IPIV, WORK, INFO) 
CHPTRI 
subroutine chptri  (  character  UPLO, 
integer  N,  
complex, dimension( * )  AP,  
integer, dimension( * )  IPIV,  
complex, dimension( * )  WORK,  
integer  INFO  
) 
CHPTRI
Download CHPTRI + dependencies [TGZ] [ZIP] [TXT]CHPTRI computes the inverse of a complex Hermitian indefinite matrix A in packed storage using the factorization A = U*D*U**H or A = L*D*L**H computed by CHPTRF.
[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**H; = 'L': Lower triangular, form is A = L*D*L**H. 
[in]  N  N is INTEGER The order of the matrix A. N >= 0. 
[in,out]  AP  AP is COMPLEX array, dimension (N*(N+1)/2) On entry, the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CHPTRF, stored as a packed triangular matrix. On exit, if INFO = 0, the (Hermitian) inverse of the original matrix, stored as a packed triangular matrix. The jth column of inv(A) is stored in the array AP as follows: if UPLO = 'U', AP(i + (j1)*j/2) = inv(A)(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j1)*(2nj)/2) = inv(A)(i,j) for j<=i<=n. 
[in]  IPIV  IPIV is INTEGER array, dimension (N) Details of the interchanges and the block structure of D as determined by CHPTRF. 
[out]  WORK  WORK is COMPLEX array, dimension (N) 
[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 110 of file chptri.f.