# naginterfaces.library.blas.dnhous¶

naginterfaces.library.blas.dnhous(delta, y, zeta, z)[source]

dnhous applies a NAG (as opposed to LINPACK) style real elementary reflection to a real vector.

For full information please refer to the NAG Library document for f06ft

https://www.nag.com/numeric/nl/nagdoc_28.7/flhtml/f06/f06ftf.html

Parameters
deltafloat

The original scalar .

yfloat, array-like, shape

The original vector .

zetafloat

The scalar , as returned by dnhousg().

If , is assumed to be the unit matrix and the transformation is skipped.

zfloat, array-like, shape

The vector , as returned by dnhousg().

Returns
deltafloat

The transformed scalar .

yfloat, ndarray, shape

The transformed vector.

Raises
NagValueError
(errno )

On entry, error in parameter .

Constraint: .

Notes

No equivalent traditional C interface for this routine exists in the NAG Library.

dnhous applies a real elementary reflection (Householder matrix) , as generated by dnhousg(), to a given real vector:

where is an -element real vector and a real scalar.