naginterfaces.library.lapackeig.dormrz¶
- naginterfaces.library.lapackeig.dormrz(side, trans, l, a, tau, c)[source]¶
dormrz
multiplies a general real matrix by the real orthogonal matrix from an factorization computed bydtzrzf()
.For full information please refer to the NAG Library document for f08bk
https://support.nag.com/numeric/nl/nagdoc_30.3/flhtml/f08/f08bkf.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.
- afloat, 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
dtzrzf()
.- taufloat, array-like, shape
must contain the scalar factor of the elementary reflector , as returned by
dtzrzf()
.- cfloat, array-like, shape
The matrix .
- Returns
- cfloat, 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
dormrz
is intended to be used following a call todtzrzf()
, which performs an factorization of a real upper trapezoidal matrix and represents the orthogonal 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 real 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