I think switching the sort order would probably
break a fair amount of code, and it wouldn't
necessarily be obvious that it had been broken.
For example, I suspect that there is a fair amount
of code that tests if all eigenvalues are positive by
just looking at the last one.  

Anyway, consistency is the hobgoblin of small minds.


Patrick Burns

Burns Statistics
patrick@burns-stat.com
+44 (0)20 8525 0696
http://www.burns-stat.com
(home of S Poetry and "A Guide for the Unwilling S User")

Peter Dalgaard wrote:

>Prof Brian Ripley <ripley@stats.ox.ac.uk> writes:
>
>  
>
>>That is not a symmetric matrix so the eigenvalues are potentially complex 
>>and are sorted by modulus.  There's an ambiguity in the description for 
>>that case.
>>    
>>
>
>Ah-ha! Thanks, Brian. 
>
>I wonder if we should switch to sorting by absolute value in the real
>case too, for consistency, and maybe also to avoid silly mistakes
>caused by people expecting that the first/last eigenvalues are the
>important ones.
>
>  
>


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