"A block reflector is an orthogonal, symmetric matrix that reverses a subspace whose dimension may be greater than one."
- see abstract here http://locus.siam.org/SINUM/volume-25/art_0725014.html
It is built out of many elementary reflectors.
It is also referred to as a triangular factor, and is a triangular matrix and they are used in the Householder transformation.
A reflector belonging to can be written in the form : where is the identity matrix for, is a scalar and belongs to .
Read more about Block Reflector: LAPACK Routines
Famous quotes containing the word block:
“When the landscape buckles and jerks around, when a dust column of debris rises from the collapse of a block of buildings on bodies that could have been your own, when the staves of history fall awry and the barrel of time bursts apart, some turn to prayer, some to poetry: words in the memory, a stained book carried close to the body, the notebook scribbled by hand—a center of gravity.”
—Adrienne Rich (b. 1929)