LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  spptri (UPLO, N, AP, INFO) 
SPPTRI 
subroutine spptri  (  character  UPLO, 
integer  N,  
real, dimension( * )  AP,  
integer  INFO  
) 
SPPTRI
Download SPPTRI + dependencies [TGZ] [ZIP] [TXT]SPPTRI computes the inverse of a real symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPPTRF.
[in]  UPLO  UPLO is CHARACTER*1 = 'U': Upper triangular factor is stored in AP; = 'L': Lower triangular factor is stored in AP. 
[in]  N  N is INTEGER The order of the matrix A. N >= 0. 
[in,out]  AP  AP is REAL array, dimension (N*(N+1)/2) On entry, the triangular factor U or L from the Cholesky factorization A = U**T*U or A = L*L**T, packed columnwise as a linear array. The jth column of U or L is stored in the array AP as follows: if UPLO = 'U', AP(i + (j1)*j/2) = U(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j1)*(2nj)/2) = L(i,j) for j<=i<=n. On exit, the upper or lower triangle of the (symmetric) inverse of A, overwriting the input factor U or L. 
[out]  INFO  INFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value > 0: if INFO = i, the (i,i) element of the factor U or L is zero, and the inverse could not be computed. 
Definition at line 94 of file spptri.f.