# dsyt01_aa.f - Man Page

TESTING/LIN/dsyt01_aa.f

## Synopsis

### Functions/Subroutines

subroutine dsyt01_aa (uplo, n, a, lda, afac, ldafac, ipiv, c, ldc, rwork, resid)
DSYT01

## Function/Subroutine Documentation

### subroutine dsyt01_aa (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldafac, * ) afac, integer ldafac, integer, dimension( * ) ipiv, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( * ) rwork, double precision resid)

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

NAG Ltd.

Definition at line 122 of file dsyt01_aa.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page dsyt01_aa(3) is an alias of dsyt01_aa.f(3).

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