dsyt01.f - Man Page

subroutine dsyt01 (uplo, n, a, lda, afac, ldafac, ipiv, c, ldc, rwork, resid)
DSYT01

DSYT01

Purpose:

 DSYT01 reconstructs a symmetric indefinite 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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (LDAFAC,N)
          The factored form of the matrix A.  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 DSYTRF.

LDAFAC

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

IPIV

          IPIV is INTEGER array, dimension (N)
          The pivot indices from DSYTRF.

C

          C is DOUBLE PRECISION array, dimension (LDC,N)

LDC

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

RWORK

          RWORK is DOUBLE PRECISION array, dimension (N)

RESID

          RESID is DOUBLE PRECISION
          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 122 of file dsyt01.f.