# cptt01.f - Man Page

TESTING/LIN/cptt01.f

## Synopsis

### Functions/Subroutines

subroutine cptt01 (n, d, e, df, ef, work, resid)
CPTT01

## Function/Subroutine Documentation

### subroutine cptt01 (integer n, real, dimension( * ) d, complex, dimension( * ) e, real, dimension( * ) df, complex, dimension( * ) ef, complex, dimension( * ) work, real resid)

CPTT01

Purpose:

``` CPTT01 reconstructs a tridiagonal matrix A from its L*D*L'
factorization and computes the residual
norm(L*D*L' - A) / ( n * norm(A) * EPS ),
where EPS is the machine epsilon.```
Parameters

N

```          N is INTEGER
The order of the matrix A.```

D

```          D is REAL array, dimension (N)
The n diagonal elements of the tridiagonal matrix A.```

E

```          E is COMPLEX array, dimension (N-1)
The (n-1) subdiagonal elements of the tridiagonal matrix A.```

DF

```          DF is REAL array, dimension (N)
The n diagonal elements of the factor L from the L*D*L'
factorization of A.```

EF

```          EF is COMPLEX array, dimension (N-1)
The (n-1) subdiagonal elements of the factor L from the
L*D*L' factorization of A.```

WORK

`          WORK is COMPLEX array, dimension (2*N)`

RESID

```          RESID is REAL
norm(L*D*L' - A) / (n * norm(A) * EPS)```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 91 of file cptt01.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page cptt01(3) is an alias of cptt01.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK