Re: Octave and Freemat

[David Bateman]

Sebastien Loisel wrote:
> Dear David,
>
> Thank you for your quick reply.
>
>
>     That is an error, as the code on octave-forge is not part of
>     Octave. The
>     copyright strings were recently updated in octave-forge and I believe
>
>
> OK, I see that ORTH  
> http://velveeta.che.wisc.edu/cgi-bin/cvsweb.cgi/~checkout~/octave/scripts/linear-algebra/orth.m?rev=HEAD&content-type=text/plain 
> <http://velveeta.che.wisc.edu/cgi-bin/cvsweb.cgi/%7Echeckout%7E/octave/scripts/linear-algebra/orth.m?rev=HEAD&content-type=text/plain>
> is part of Octave, while ODE45 
> http://octave.svn.sourceforge.net/viewvc/octave/trunk/octave-forge/extra/ode/inst/ode45.m?revision=HEAD&content-type=text/plain 
> <http://octave.svn.sourceforge.net/viewvc/octave/trunk/octave-forge/extra/ode/inst/ode45.m?revision=HEAD&content-type=text/plain> 
> is not. I'll just leave the copyrights alone. For those files that I 
> lift out of Octave (like ORTH), I will put a note that the file was 
> copied into Freemat, and that Freemat's not part of Octave, and 
> otherwise leave the copyright alone. Does that sound like the right idea?
>  
>
>     roots is an octave core function and not from Octave forge, so
>     send the
>     proposed patches to roots to address@hidden
>     <mailto:address@hidden>. As for octave-forge
>
>
> The correct implementation of roots.m is
>
> function z = roots(p)
>   if(any(isnan(p) | isinf(p)))
Octave deliberately doesn't support the short circuiting with the "|" 
operator, use "||" instead. See

http://www.gnu.org/software/octave/FAQ.html#MATLAB-compatibility

for a discussion of why.

>  
>   while(any(isinf(p./p(1))))
>      p=p(2:end);
>   end
Its bad form to use a loop here, but this is the cause of the issue you 
saw. It would be better to write that as

f = find (p ./ max(p));
p = p (f(1):end);

assuming p is a vector of cause, so perhaps you should move your "vec" 
statement before this. I'll supply a patch to Octave's roots function 
based on this

D.