# zppt01.f - Man Page

TESTING/LIN/zppt01.f

## Synopsis

### Functions/Subroutines

subroutine zppt01 (uplo, n, a, afac, rwork, resid)
ZPPT01

## Function/Subroutine Documentation

### subroutine zppt01 (character uplo, integer n, complex*16, dimension( * ) a, complex*16, dimension( * ) afac, double precision, dimension( * ) rwork, double precision resid)

ZPPT01

Purpose:

``` ZPPT01 reconstructs a Hermitian positive definite packed matrix A
from its L*L' or U'*U factorization and computes the residual
norm( L*L' - A ) / ( N * norm(A) * EPS ) or
norm( U'*U - A ) / ( N * norm(A) * EPS ),
where EPS is the machine epsilon, L' is the conjugate transpose of
L, and U' is the conjugate transpose of U.```
Parameters

UPLO

```          UPLO is CHARACTER*1
Specifies whether the upper or lower triangular part of the
Hermitian 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 COMPLEX*16 array, dimension (N*(N+1)/2)
The original Hermitian matrix A, stored as a packed
triangular matrix.```

AFAC

```          AFAC is COMPLEX*16 array, dimension (N*(N+1)/2)
On entry, the factor L or U from the L*L' or U'*U
factorization of A, stored as a packed triangular matrix.
Overwritten with the reconstructed matrix, and then with the
difference L*L' - A (or U'*U - A).```

RWORK

`          RWORK is DOUBLE PRECISION array, dimension (N)`

RESID

```          RESID is DOUBLE PRECISION
If UPLO = 'L', norm(L*L' - A) / ( N * norm(A) * EPS )
If UPLO = 'U', norm(U'*U - A) / ( N * norm(A) * EPS )```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 94 of file zppt01.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page zppt01(3) is an alias of zppt01.f(3).

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