Re: lsode parameters slows down solution ?

[Oz Nahum]

Hi Liam,
Thanks for the answer. Sorry it took me a while to answer too.
Today I ran the codes again, including the files you sent me.

Well, the results are surprising.... I guess that in my previous
account about Octave being slower, I did a mistake in preparing the
table. And the results I've reported to be slow are from Matlab.
Actually Octave's ODE solver finished much faster. Both on cold start
and on further runs.

The syntax is a bit obscure and not clear, but after I got it, thanks
to your replies I can handle more problems and I guess octave will be
faster.


Here's the output get from octave:
octave:1> batch1c
Elapsed time is 0.181664 seconds.
octave:2> batch1c
Elapsed time is 0.049692 seconds.
octave:3> batch1_lee
Elapsed time is 0.047575 seconds.


Here's the output get from Matlab:
>> batch1_matlab

Elapsed time is 1.267878 seconds.
>> batch1_matlab
Elapsed time is 0.253152 seconds.
>>

Last year I had another big task I wrote in Matlab and compared to
Octave, and than Matlab significantly slower.

Today I reviewed this problem in Octave and Matlab, and Octave took
25% of Matlab's time.

This is really great. There is no reason any more to use Matlab.

Thanks again for you answers.



On Fri, Apr 2, 2010 at 4:51 AM, Liam Groener <address@hidden> wrote:
> Hi,
> I had some time today, so I looked at your files a little more closely. The 
> attached files reflect what I think the coding should be for both Octave and 
> Scilab. (I don't have Matlab.) These are for the full equation with all seven 
> parameters. On my iMac, Octave took 0.23 sec and Scilab took 0.37 sec to 
> integrate the de's.
> The plots generated by both programs look identical. I looked at the final 
> concentrations too:
> Scilab:
> -->c(:,1033)
>  ans  =
>
>    6.778D-12
>    8.5
>    0.3921311
> Octave:
>  >> c(1033,:)
> ans =
>
>   5.1757e-10   8.5000e+00   3.9213e-01
>
> Lee G.
>



-- 
Oz Nahum
Graduate Student
Zentrum für Angewandte Geologie
Universität Tübingen

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