# naginterfaces.library.blas.zhpr2¶

naginterfaces.library.blas.zhpr2(uplo, alpha, x, y, ap)[source]

zhpr2 computes the rank-2 update of a complex Hermitian matrix stored in packed form.

For full information please refer to the NAG Library document for f06ss

https://www.nag.com/numeric/nl/nagdoc_28.7/flhtml/f06/f06ssf.html

Parameters
uplostr, length 1

Specifies whether the upper or lower triangular part of is stored.

The upper triangular part of is stored.

The lower triangular part of is stored.

alphacomplex

The scalar .

xcomplex, array-like, shape

The -element vector .

ycomplex, array-like, shape

The -element vector .

apcomplex, array-like, shape

The Hermitian matrix , packed by columns.

Returns
apcomplex, ndarray, shape

The updated matrix . The imaginary parts of the diagonal elements are set to zero.

Raises
NagValueError
(errno )

On entry, error in parameter .

Constraint: or .

(errno )

On entry, error in parameter .

Constraint: .

(errno )

On entry, error in parameter .

Constraint: .

(errno )

On entry, error in parameter .

Constraint: .

Notes

In the NAG Library the traditional C interface for this routine uses a different algorithmic base. Please contact NAG if you have any questions about compatibility.

zhpr2 performs the Hermitian rank-2 update operation

where is an complex Hermitian matrix, stored in packed form, and are -element complex vectors, and is a complex scalar.