Preload (cardiology): Difference between revisions
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→Calculation: Preload is measured in pressure units (mm Hg). |
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"A '''block reflector''' is an orthogonal, symmetric [[matrix (mathematics)|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 reflector]]s. | |||
It is also referred to as a [[triangular factor]], and is a [[triangular matrix]] and they are used in the [[Householder transformation]]. | |||
A reflector <math> Q </math> belonging to <math>\mathcal M_n(\R) </math> can be written in the form : | |||
<math> Q = I -auu^T </math> where <math>I</math> is the [[identity matrix]] for <math>\mathcal M_n(\R) </math> , <math>a</math> is a [[Scalar (mathematics)|scalar]] and <math>u</math> belongs to <math>\mathcal \R^n </math> . | |||
==LAPACK routines== | |||
Here are some of the [[LAPACK]] routines that apply to block reflectors | |||
* "*larft" forms the triangular vector T of a block reflector H=I-VTVH. | |||
* "*larzb" applies a block reflector or its [[transpose]]/[[conjugate transpose]] as returned by "*tzrzf" to a general [[matrix (mathematics)|matrix]]. | |||
* "*larzt" forms the triangular vector T of a block reflector H=I-VTVH as returned by "*tzrzf". | |||
* "*larfb" applies a block reflector or its [[transpose]]/[[conjugate transpose]] to a general rectangular matrix. | |||
==See also== | |||
* [[Reflection (mathematics)]] | |||
* [[Householder transformation]] | |||
* [[Unitary matrix]] | |||
* [[Triangular matrix]] | |||
[[Category:Matrices]] | |||
{{Linear-algebra-stub}} | |||
{{compu-prog-stub}} |
Revision as of 22:51, 4 January 2014
"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 .
LAPACK routines
Here are some of the LAPACK routines that apply to block reflectors
- "*larft" forms the triangular vector T of a block reflector H=I-VTVH.
- "*larzb" applies a block reflector or its transpose/conjugate transpose as returned by "*tzrzf" to a general matrix.
- "*larzt" forms the triangular vector T of a block reflector H=I-VTVH as returned by "*tzrzf".
- "*larfb" applies a block reflector or its transpose/conjugate transpose to a general rectangular matrix.