chptri(3)

chptri3

Part of chptri.f(3).

Usage

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.

Definition at line 108 of file chptri.f.

Releases

14 releases since Debian 1.3 (Bo); the text changed 11 times.

  1. 1.3
  2. 2.0–2.2
  3. 3.0
  4. 3.1
  5. 4.0
  6. 7
  7. 8
  8. 9
  9. 10
  10. 11
  11. 12
  12. Arch

Author

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From lapack-doc 3.12.1-2 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.