chptri.f man page

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)

CHPTRI  

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.

Date:

December 2016

Definition at line 111 of file chptri.f.

Author

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Referenced By

The man page chptri(3) is an alias of chptri.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK