SRC/dsptri.f(3)            Library Functions Manual            SRC/dsptri.f(3)

NAME
       SRC/dsptri.f

SYNOPSIS
   Functions/Subroutines
       subroutine dsptri (uplo, n, ap, ipiv, work, info)
           DSPTRI

Function/Subroutine Documentation
   subroutine dsptri (character uplo, integer n, double precision, dimension(
       * ) ap, integer, dimension( * ) ipiv, double precision, dimension( * )
       work, integer info)
       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.

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           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 j-th column
                     of inv(A) is stored in the array AP as follows:
                     if UPLO = 'U', AP(i + (j-1)*j/2) = inv(A)(i,j) for 1<=i<=j;
                     if UPLO = 'L',
                        AP(i + (j-1)*(2n-j)/2) = inv(A)(i,j) for j<=i<=n.

           IPIV

                     IPIV is INTEGER array, dimension (N)
                     Details of the interchanges and the block structure of D
                     as determined by DSPTRF.

           WORK

                     WORK is DOUBLE PRECISION array, dimension (N)

           INFO

                     INFO is INTEGER
                     = 0: successful exit
                     < 0: if INFO = -i, the i-th 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.

       Definition at line 108 of file dsptri.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/dsptri.f(3)