Re: Inverse Matrix Function appears a bit wonky

[Robert A. Macy]

I did pull the matrix out of my ...random matrix generating
head. I'm one of those people that have the good fortune of
"reverse" ESP, inherently finding the wrong stuff.  

--Whether selecting a test matrix, accidentally using ctrl
arrow key during editing [which always bombs octave], or
simply needing to have very large matrices [which also
bombs octave]

But ocatve is still GOLD! Kudos to John Eaton for his past,
and continuing efforts.  

            - Robert -

On Fri, 5 Nov 2004 13:00:17 -0500 (EST)
 Przemek Klosowski <address@hidden> wrote:
> 
>     For 2x2 matrices made up of integers between -3 and
> +3, the answer is
>     obviously 14.4%. If you can't see that at first
> sight, try running the
>     attached script. Sheesh!
> 
>  Very good! but, people don't use negative numbers when
> they pull the
>  random matrices out of their... mental random number
> generator. When
>  you use apos=2*rand(k,k)*maxval (which is equivalent to
> your a
>  plus a constant matrix ones(k,k)*maxval, the probability
> drops by
>  a factor of two, to 7%. Is there a simple explanation of
> that?
> 
>  OK, the official results are in: 3x3 {0..9}-valued
> matrices it's 4%, and
>  2% for 4x4 matrices, and .5% for 5x5 matrices. Funny.
> The originator
>  of this thread had 1-in-60 chance of picking a singular
> matrix.
> 
> 
> 
>
-------------------------------------------------------------
> Octave is freely available under the terms of the GNU
> GPL.
> 
> Octave's home on the web:  http://www.octave.org
> How to fund new projects:
>  http://www.octave.org/funding.html
> Subscription information:
>  http://www.octave.org/archive.html
>
-------------------------------------------------------------
> 



-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------