dsptri.f(3)

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.

    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.

Date:
    November 2011

Definition at line 110 of file dsptri.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.