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Re: ConditionNumber

  • To: mathgroup at smc.vnet.net
  • Subject: [mg89532] Re: ConditionNumber
  • From: "Dana DeLouis" <dana.del at gmail.com>
  • Date: Thu, 12 Jun 2008 02:57:31 -0400 (EDT)

> if you try: Norm->2 you get the message ...

 

Hi.  I have Ver 6, and not 6.0.2

 

m = RandomInteger[{-9, 9}, {20, 20}] // N;

 

If I do MatrixConditionNumber[m, Norm->2], it returns unevaluated.
However, 

 

MatrixConditionNumber[m, 2]

65.3896

 

I don't understand the online code, and the numbers are slightly different,
but is this the same thing?  I'm not sure from reading the code.

 

MatrixConditionNumber[m, LUDecomposition[m], 2]

65.4541

 

As a side note, the Infinity Norm is now:

 

LUDecomposition[m] // Last

281.188

 

and not...

 

MatrixConditionNumber[m, \[Infinity]]

281.188

 

-- 
HTH :>)
Dana DeLouis
Mathematica 6.01 (Windows Vista)
Having to Read 5.0 Help Files

 

 

"dh" <dh at metrohm.ch> wrote in message news:g2lnld$iei$1 at smc.vnet.net...

> 
> 
> Hello,
> 
> the entry in the manual about the condition number reads:
> 
> "LinearAlgebra`MatrixConditionNumber[mat,Norm->p]  p-norm approximate 
> 
> condition number of a matrix, where p may be 1, 2, or \[Infinity]"
> 
> In version 6.0.2, if you try: Norm->2 you get the message that only 1 or 
> 
> Infinity is allowed.
> 
> As the 2 norm is the most common norm, it is hard to see why it should 
> 
> not work.
> 
> Daniel
> 
> 
> 
> 
> 
> -- 
> 
> 
> 
> Daniel Huber
> 
> Metrohm Ltd.
> 
> Oberdorfstr. 68
> 
> CH-9100 Herisau
> 
> Tel. +41 71 353 8585, Fax +41 71 353 8907
> 
> E-Mail:<mailto:dh at metrohm.com>
> 
> Internet:<http://www.metrohm.com>
> 
> 
>




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