naginterfaces.library.lapackeig.zunmrz

naginterfaces.library.lapackeig.zunmrz(side, trans, l, a, tau, c)[source]

zunmrz multiplies a general complex matrix by the complex unitary matrix from an factorization computed by ztzrzf().

For full information please refer to the NAG Library document for f08bx

https://www.nag.com/numeric/nl/nagdoc_28.6/flhtml/f08/f08bxf.html

Parameters
sidestr, length 1

Indicates how or is to be applied to .

or is applied to from the left.

or is applied to from the right.

transstr, length 1

Indicates whether or is to be applied to .

is applied to .

is applied to .

lint

, the number of columns of the matrix containing the meaningful part of the Householder reflectors.

acomplex, array-like, shape

Note: the required extent for this argument in dimension 2 is determined as follows: if : ; if : ; otherwise: .

The th row of must contain the vector which defines the elementary reflector , for , as returned by ztzrzf().

taucomplex, array-like, shape

must contain the scalar factor of the elementary reflector , as returned by ztzrzf().

ccomplex, array-like, shape

The matrix .

Returns
ccomplex, ndarray, shape

is overwritten by or or or as specified by and .

Raises
NagValueError
(errno )

On entry, error in parameter .

Constraint: or .

(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: .

(errno )

On entry, error in parameter .

Constraint: .

(errno )

On entry, error in parameter .

Constraint: .

(errno )

On entry, error in parameter .

Constraint: .

Notes

zunmrz is intended to be used following a call to ztzrzf(), which performs an factorization of a real upper trapezoidal matrix and represents the unitary matrix as a product of elementary reflectors.

This function may be used to form one of the matrix products

overwriting the result on , which may be any complex rectangular matrix.

References

Anderson, E, Bai, Z, Bischof, C, Blackford, S, Demmel, J, Dongarra, J J, Du Croz, J J, Greenbaum, A, Hammarling, S, McKenney, A and Sorensen, D, 1999, LAPACK Users’ Guide, (3rd Edition), SIAM, Philadelphia, https://www.netlib.org/lapack/lug