# zpttrf (3) - Linux Man Pages

zpttrf.f -

## SYNOPSIS

### Functions/Subroutines

subroutine zpttrf (N, D, E, INFO)
ZPTTRF

## Function/Subroutine Documentation

### subroutine zpttrf (integerN, double precision, dimension( * )D, complex*16, dimension( * )E, integerINFO)

ZPTTRF

Purpose:

``` ZPTTRF computes the L*D*L**H factorization of a complex Hermitian
positive definite tridiagonal matrix A.  The factorization may also
be regarded as having the form A = U**H *D*U.
```

Parameters:

N

```          N is INTEGER
The order of the matrix A.  N >= 0.
```

D

```          D is DOUBLE PRECISION array, dimension (N)
On entry, the n diagonal elements of the tridiagonal matrix
A.  On exit, the n diagonal elements of the diagonal matrix
D from the L*D*L**H factorization of A.
```

E

```          E is COMPLEX*16 array, dimension (N-1)
On entry, the (n-1) subdiagonal elements of the tridiagonal
matrix A.  On exit, the (n-1) subdiagonal elements of the
unit bidiagonal factor L from the L*D*L**H factorization of A.
E can also be regarded as the superdiagonal of the unit
bidiagonal factor U from the U**H *D*U factorization of A.
```

INFO

```          INFO is INTEGER
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value
> 0: if INFO = k, the leading minor of order k is not
positive definite; if k < N, the factorization could not
be completed, while if k = N, the factorization was
completed, but D(N) <= 0.
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 93 of file zpttrf.f.

## Author

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