dsyt01_3.f - Man Page

TESTING/LIN/dsyt01_3.f

Synopsis

Functions/Subroutines

subroutine dsyt01_3 (uplo, n, a, lda, afac, ldafac, e, ipiv, c, ldc, rwork, resid)
DSYT01_3

Function/Subroutine Documentation

subroutine dsyt01_3 (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldafac, * ) afac, integer ldafac, double precision, dimension( * ) e, integer, dimension( * ) ipiv, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( * ) rwork, double precision resid)

DSYT01_3

Purpose:

 DSYT01_3 reconstructs a symmetric indefinite matrix A from its
 block L*D*L' or U*D*U' factorization computed by DSYTRF_RK
 (or DSYTRF_BK) 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)
          Diagonal of the block diagonal matrix D and factors U or L
          as computed by DSYTRF_RK and DSYTRF_BK:
            a) ONLY diagonal elements of the symmetric block diagonal
               matrix D on the diagonal of A, i.e. D(k,k) = A(k,k);
               (superdiagonal (or subdiagonal) elements of D
                should be provided on entry in array E), and
            b) If UPLO = 'U': factor U in the superdiagonal part of A.
               If UPLO = 'L': factor L in the subdiagonal part of A.

LDAFAC

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

E

          E is DOUBLE PRECISION array, dimension (N)
          On entry, contains the superdiagonal (or subdiagonal)
          elements of the symmetric block diagonal matrix D
          with 1-by-1 or 2-by-2 diagonal blocks, where
          If UPLO = 'U': E(i) = D(i-1,i),i=2:N, E(1) not referenced;
          If UPLO = 'L': E(i) = D(i+1,i),i=1:N-1, E(N) not referenced.

IPIV

          IPIV is INTEGER array, dimension (N)
          The pivot indices from DSYTRF_RK (or DSYTRF_BK).

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 138 of file dsyt01_3.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page dsyt01_3(3) is an alias of dsyt01_3.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK