DSPTRI (3)  Linux Manuals
NAME
dsptri.f 
SYNOPSIS
Functions/Subroutines
subroutine dsptri (UPLO, N, AP, IPIV, WORK, INFO)
DSPTRI
Function/Subroutine Documentation
subroutine dsptri (characterUPLO, integerN, double precision, dimension( * )AP, integer, dimension( * )IPIV, double precision, dimension( * )WORK, integerINFO)
DSPTRI
Purpose:

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.
Parameters:

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.
NN is INTEGER The order of the matrix A. N >= 0.
APAP 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.
IPIVIPIV is INTEGER array, dimension (N) Details of the interchanges and the block structure of D as determined by DSPTRF.
WORKWORK is DOUBLE PRECISION array, dimension (N)
INFOINFO 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.
Author:

Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
 November 2011
Definition at line 110 of file dsptri.f.
Author
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