chptri.f(3)

NAME
chptri.f

SYNOPSIS

  Functions/Subroutines
subroutine chptri (UPLO, N, AP, IPIV, WORK, INFO)
CHPTRI

Function/Subroutine Documentation

  subroutine chptri (character UPLO, integer N, complex, dimension( * ) AP, integer, dimension( * ) IPIV, complex, dimension( * ) WORK, integer INFO)

Purpose:

     CHPTRI computes the inverse of a complex Hermitian indefinite matrix
     A in packed storage using the factorization A = U*D*U**H or
     A = L*D*L**H computed by CHPTRF.

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**H;
              = 'L':  Lower triangular, form is A = L*D*L**H.

    N

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

    AP

              AP is COMPLEX 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 CHPTRF,
              stored as a packed triangular matrix.
              On exit, if INFO = 0, the (Hermitian) 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 CHPTRF.

    WORK

              WORK is COMPLEX 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 chptri.f.

Author

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