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What function to use to find matrix condition number?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg114407] What function to use to find matrix condition number?
  • From: "Nasser M. Abbasi" <nma at 12000.org>
  • Date: Fri, 3 Dec 2010 05:22:19 -0500 (EST)
  • Reply-to: nma at 12000.org

This is version 8:

I'd like to use LinearAlgebra`MatrixConditionNumber to find
condition number of some matrix.

btw, This command lists the functions in linear algebra.
Names["LinearAlgebra`*"]

But Mathematica says this package is now obsolete, and
functionality is now in the kernel.

<<LinearAlgebra`
General::obspkg: {At Line = 3, the input was:,
<<LinearAlgebra`,LinearAlgebra`} is now obsolete. The
legacy version being loaded may conflict with current
Mathematica functionality. See the Compatibility Guide for
updating information. >>

But When I follow the above, I get to page, where at the bottom
it shows 3 functions, one of them is MatrixConditionNumber,
but it does not show what replaced it in the kernel, instead
it points to a link to MathSource article:

"These functions were available in previous versions of Mathematica
and are now available on the web at
library.wolfram.com/infocenter/MathSource/6770"

?

So, is there no build-in function to compute condition number now
in Mathematica?

I know I can find the max eigenvalue, divide it by the min
eigenvalue (absolute values), and this gives me the condition
number. But should not such a function be part of the system?

Or may be I overlooked it? I did search for it, can't find it
in the documenation center.

btw, I did also try the natural language interface also, and I asked
W/ALpha by typing

      = matrix condition number

but it replied back with a chemical formula C16 H13 C1 N2 O, named diazepam, which is not what I wanted.

thanks,
--Nasser


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