sspcon(3)

sspcon3

Part of sspcon.f(3).

Usage

Functions/Subroutines

subroutine sspcon (uplo, n, ap, ipiv, anorm, rcond, work, iwork, info)
SSPCON

Function/Subroutine Documentation

subroutine sspcon (character uplo, integer n, real, dimension( * ) ap, integer, dimension( * ) ipiv, real anorm, real rcond, real, dimension( * ) work, integer, dimension( * ) iwork, integer info)

SSPCON

Purpose:

!>
!> SSPCON estimates the reciprocal of the condition number (in the
!> 1-norm) of a real symmetric packed matrix A using the factorization
!> A = U*D*U**T or A = L*D*L**T computed by SSPTRF.
!>
!> An estimate is obtained for norm(inv(A)), and the reciprocal of the
!> condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
!> 

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 REAL array, dimension (N*(N+1)/2)
!>          The block diagonal matrix D and the multipliers used to
!>          obtain the factor U or L as computed by SSPTRF, stored as a
!>          packed triangular matrix.
!> 

IPIV

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

ANORM

!>          ANORM is REAL
!>          The 1-norm of the original matrix A.
!> 

RCOND

!>          RCOND is REAL
!>          The reciprocal of the condition number of the matrix A,
!>          computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an
!>          estimate of the 1-norm of inv(A) computed in this routine.
!> 

WORK

!>          WORK is REAL array, dimension (2*N)
!> 

IWORK

!>          IWORK is INTEGER array, dimension (N)
!> 

INFO

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!> 

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 123 of file sspcon.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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