TESTING/LIN/spst01.f(3) Library Functions Manual TESTING/LIN/spst01.f(3)

TESTING/LIN/spst01.f


subroutine spst01 (uplo, n, a, lda, afac, ldafac, perm, ldperm, piv, rwork, resid, rank)
SPST01

SPST01

Purpose:

!>
!> SPST01 reconstructs a symmetric positive semidefinite matrix A
!> from its L or U factors and the permutation matrix P and computes
!> the residual
!>    norm( P*L*L'*P' - A ) / ( N * norm(A) * EPS ) or
!>    norm( P*U'*U*P' - A ) / ( N * norm(A) * EPS ),
!> where 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 (LDA,N)
!>          The original symmetric matrix A.
!> 

LDA

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

AFAC

!>          AFAC is REAL array, dimension (LDAFAC,N)
!>          The factor L or U from the L*L' or U'*U
!>          factorization of A.
!> 

LDAFAC

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

PERM

!>          PERM is REAL array, dimension (LDPERM,N)
!>          Overwritten with the reconstructed matrix, and then with the
!>          difference P*L*L'*P' - A (or P*U'*U*P' - A)
!> 

LDPERM

!>          LDPERM is INTEGER
!>          The leading dimension of the array PERM.
!>          LDAPERM >= max(1,N).
!> 

PIV

!>          PIV is INTEGER array, dimension (N)
!>          PIV is such that the nonzero entries are
!>          P( PIV( K ), K ) = 1.
!> 

RWORK

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

RESID

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

RANK

!>          RANK is INTEGER
!>          number of nonzero singular values of A.
!> 

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 132 of file spst01.f.

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