DPPTRI(3)
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 DPPTRF
SYNOPSIS
 SUBROUTINE DPPTRI(

UPLO, N, AP, INFO )

CHARACTER
UPLO

INTEGER
INFO, N

DOUBLE
PRECISION AP( * )
PURPOSE
DPPTRI 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 DPPTRF.
ARGUMENTS
 UPLO (input) CHARACTER*1

= 'U': Upper triangular factor is stored in AP;
= 'L': Lower triangular factor is stored in AP.
 N (input) INTEGER

The order of the matrix A. N >= 0.
 AP (input/output) DOUBLE PRECISION 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.
 INFO (output) 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.