TESTING/LIN/sspt01.f(3) Library Functions Manual TESTING/LIN/sspt01.f(3)

TESTING/LIN/sspt01.f


subroutine sspt01 (uplo, n, a, afac, ipiv, c, ldc, rwork, resid)
SSPT01

SSPT01

Purpose:

!>
!> SSPT01 reconstructs a symmetric indefinite packed matrix A from its
!> block L*D*L' or U*D*U' factorization and computes the residual
!>      norm( C - A ) / ( N * norm(A) * EPS ),
!> where C is the reconstructed matrix and EPS is the machine epsilon.
!> 

Parameters

UPLO
!>          UPLO is CHARACTER*1
!>          Specifies whether the upper or lower triangular part of the
!>          symmetric matrix A is stored:
!>          = 'U':  Upper triangular
!>          = 'L':  Lower triangular
!> 

N

!>          N is INTEGER
!>          The number of rows and columns of the matrix A.  N >= 0.
!> 

A

!>          A is REAL array, dimension (N*(N+1)/2)
!>          The original symmetric matrix A, stored as a packed
!>          triangular matrix.
!> 

AFAC

!>          AFAC is REAL array, dimension (N*(N+1)/2)
!>          The factored form of the matrix A, stored as a packed
!>          triangular matrix.  AFAC contains the block diagonal matrix D
!>          and the multipliers used to obtain the factor L or U from the
!>          block L*D*L' or U*D*U' factorization as computed by SSPTRF.
!> 

IPIV

!>          IPIV is INTEGER array, dimension (N)
!>          The pivot indices from SSPTRF.
!> 

C

!>          C is REAL array, dimension (LDC,N)
!> 

LDC

!>          LDC is INTEGER
!>          The leading dimension of the array C.  LDC >= max(1,N).
!> 

RWORK

!>          RWORK is REAL array, dimension (N)
!> 

RESID

!>          RESID is REAL
!>          If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS )
!>          If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS )
!> 

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 109 of file sspt01.f.

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