KpNorm: Difference between revisions

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Created page with "{{Function |name=kpNorm |desc=Computes the (k,p)-norm of an operator |rel=KyFanNorm<br />SchattenNorm<br />TraceNorm |upd=December 1, 2012 |v=1.00}} <tt>'''kpN..."
 
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|desc=Computes the [[(k,p)-norm]] of an operator
|desc=Computes the [[(k,p)-norm]] of an operator
|rel=[[KyFanNorm]]<br />[[SchattenNorm]]<br />[[TraceNorm]]
|rel=[[KyFanNorm]]<br />[[SchattenNorm]]<br />[[TraceNorm]]
|upd=December 1, 2012
|upd=December 3, 2012
|v=1.00}}
|v=1.01}}
<tt>'''kpNorm'''</tt> is a [[List of functions|function]] that computes the [[(k,p)-norm]] of an operator (i.e., the p-norm of the vector of its k largest singular values). It works with both full and sparse matrices.
<tt>'''kpNorm'''</tt> is a [[List of functions|function]] that computes the [[(k,p)-norm]] of an operator (i.e., the p-norm of the vector of its k largest singular values). It works with both full and sparse matrices.



Revision as of 15:12, 3 December 2012

kpNorm
Computes the (k,p)-norm of an operator

Other toolboxes required none
Related functions KyFanNorm
SchattenNorm
TraceNorm

kpNorm is a function that computes the (k,p)-norm of an operator (i.e., the p-norm of the vector of its k largest singular values). It works with both full and sparse matrices.

Syntax

  • NRM = kpNorm(X,K,P)

Argument descriptions

  • X: An operator to have its (K,P)-norm computed.
  • K: A positive integer.
  • P: A real number ≥ 1, or Inf.

Examples

Generalizes the operator, trace, Ky Fan, and Schatten norms

The (K,P)-norm is simply the usual operator norm when K = 1 or P = Inf:

>> X = rand(3);
>> [norm(X), kpNorm(X,1,Inf), kpNorm(X,2,Inf), kpNorm(X,3,Inf), kpNorm(X,1,5)]

ans =

       1.0673       1.0673       1.0673       1.0673       1.0673

When P = 1 and K is the size of X, this norm reduces to the trace norm:

>> [kpNorm(X,3,1), TraceNorm(X)]

ans =

       1.6482       1.6482

More generally, when P = 1 this norm reduces to the Ky Fan K-norm:

>> [kpNorm(X,2,1), KyFanNorm(X,2)]

ans =

       1.5816       1.5816

Similarly, when K = min(size(X)) this norm reduces to the Schatten P-norm:

>> [kpNorm(X,3,4), SchattenNorm(X,4)]

ans =

       1.0814       1.0814