LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  dsptri (UPLO, N, AP, IPIV, WORK, INFO) 
DSPTRI 
subroutine dsptri  (  character  UPLO, 
integer  N,  
double precision, dimension( * )  AP,  
integer, dimension( * )  IPIV,  
double precision, dimension( * )  WORK,  
integer  INFO  
) 
DSPTRI
Download DSPTRI + dependencies [TGZ] [ZIP] [TXT]DSPTRI computes the inverse of a real symmetric indefinite matrix A in packed storage using the factorization A = U*D*U**T or A = L*D*L**T computed by DSPTRF.
[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]  AP  AP is DOUBLE PRECISION 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 DSPTRF, stored as a packed triangular matrix. On exit, if INFO = 0, the (symmetric) 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 DSPTRF. 
[out]  WORK  WORK is DOUBLE PRECISION 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 dsptri.f.