spptri (l)  Linux Man Pages
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
Command to display spptri
manual in Linux: $ man l spptri
NAME
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
SYNOPSIS
 SUBROUTINE SPPTRI(

UPLO, N, AP, INFO )

CHARACTER
UPLO

INTEGER
INFO, N

REAL
AP( * )
PURPOSE
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.
ARGUMENTS
 UPLO (input) CHARACTER*1

= aqUaq: Upper triangular factor is stored in AP;
= aqLaq: Lower triangular factor is stored in AP.
 N (input) INTEGER

The order of the matrix A. N >= 0.
 AP (input/output) 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 = aqUaq, AP(i + (j1)*j/2) = U(i,j) for 1<=i<=j;
if UPLO = aqLaq, 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.
Pages related to spptri
 spptri (3)
 spptrf (l)  computes the Cholesky factorization of a real symmetric positive definite matrix A stored in packed format
 spptrs (l)  solves a system of linear equations A*X = B with a symmetric positive definite matrix A in packed storage using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPPTRF
 sppcon (l)  estimates the reciprocal of the condition number (in the 1norm) of a real symmetric positive definite packed matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPPTRF
 sppequ (l)  computes row and column scalings intended to equilibrate a symmetric positive definite matrix A in packed storage and reduce its condition number (with respect to the twonorm)
 spprfs (l)  improves the computed solution to a system of linear equations when the coefficient matrix is symmetric positive definite and packed, and provides error bounds and backward error estimates for the solution
 sppsv (l)  computes the solution to a real system of linear equations A * X = B,
 sppsvx (l)  uses the Cholesky factorization A = U**T*U or A = L*L**T to compute the solution to a real system of linear equations A * X = B,