# dspt01.f - Man Page

TESTING/LIN/dspt01.f

## Synopsis

### Functions/Subroutines

subroutine dspt01 (uplo, n, a, afac, ipiv, c, ldc, rwork, resid)
DSPT01

## Function/Subroutine Documentation

### subroutine dspt01 (character uplo, integer n, double precision, dimension( * ) a, double precision, dimension( * ) afac, integer, dimension( * ) ipiv, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( * ) rwork, double precision resid)

DSPT01

Purpose:

``` DSPT01 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 DOUBLE PRECISION array, dimension (N*(N+1)/2)
The original symmetric matrix A, stored as a packed
triangular matrix.```

AFAC

```          AFAC is DOUBLE PRECISION 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 DSPTRF.```

IPIV

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

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 109 of file dspt01.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page dspt01(3) is an alias of dspt01.f(3).

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