numpy (matrix solver) - python vs. matlab

someone newsboost at gmail.com
Fri May 4 09:36:09 EDT 2012


On 05/04/2012 06:15 AM, Russ P. wrote:
> On May 3, 4:59 pm, someone<newsbo... at gmail.com>  wrote:
>> On 05/04/2012 12:58 AM, Russ P. wrote:
>> Ok, but I just don't understand what's in the "empirical" category, sorry...
>
> I didn't look it up, but as far as I know, empirical just means based
> on experiment, which means based on measured data. Unless I am

FEM based on measurement data? Still, I don't understand it, sorry.

> mistaken , a finite element analysis is not based on measured data.

I'm probably a bit narrow-thinking because I just worked with this small 
FEM-program (in Matlab), but can you please give an example of a 
matrix-problem that is based on measurement data?

> Yes, the results can be *compared* with measured data and perhaps
> calibrated with measured data, but those are not the same thing.

Exactly. That's why I don't understand what solving a matrix system 
using measurement/empirical data, could typically be an example of...?

> I agree with Steven D's comment above, and I will reiterate that a
> condition number of 1e6 would not inspire confidence in me. If I had a
> condition number like that, I would look for a better model. But
> that's just a gut reaction, not a hard scientific rule.

I don't have any better model and don't know anything better. I still 
think that 5% accuracy is good enough and that nobody needs 6-digits 
precision for practical/engineering/empirical work... Maybe quantum 
physicists needs more than 6 digits of accuracy, but most 
practical/engineering problems are ok with an accuracy of 5%, I think, 
IMHO... Please tell me if I'm wrong.





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