Re Re: [Pytables-users] Suggestions for storing mutlidimensionnal data in several pytables arrays

[<phi...@ho...>]

Francesc Altet wrote:

>A Tuesday 06 September 2005 16:08, phi...@ho... va escriure:
>  
>
>>Sorry that doesn't seem clear.
>>No limitations of pytables.
>>It's much more that i'm not allowed to use table.
>>Arrays are more appreciated to achieve my goal .
>>    
>>
>
>Ok. But it's a pity because using the filtering capabilities in Table
>objects, like:
>
>[r['pressure'] for r in table if r['latitude'] == X and r['latitude'] == Y]
>
>is very powerful to do what you are willing to.
>  
>
Of course, using python list comprehension in tables is really 
powerfull. But i can't actually use tables. I have to use arrays.

>  
>
>>That could be a good starting point. I only need an ordered list
>>containing path of each array of system parameters.
>>For example, the attribute could be
>>['/parameters/longitude','/parameters/latitude','/parameters/time']
>>    
>>
>
>Definitely, that could be a solution if you want to stick with arrays.
>
>  
>
>>In fact, i'm joining Norbert Nemec in his post from 2005-01-24 11:51 to
>>request a convention in pytables to store not only data but also a way
>>to link the data.
>>
>>Here is thye situation, better represented:
>>    
>>
>[snipped]
>
>Ok. I understand better now. With that, what you want is something
>similar to:
>
>pressure.where(pressure.axis.longitude == 0.2 and
>               pressure.axis.latitude == 0.45 )
>
>isn't it?
>
>Well, I must recognize that the idea is pretty nice. In addition, if
>values in latitude and longitude have a direct mapping into indices
>(as you seem to suggest), then a binary search on axis could be made
>so that finding the indexes should be a very fast operation.
>
>Well, I think I'll put this suggestion in our TODO file.
>
>Thanks for your detailed explanation!
>  
>
That's exactly the idea behind all. And you go further with the 
suggestion about the direct mapping into indices. That could be very 
powerfull.
Thanks a lot for taking in account new improvements.
Of course, i can give you a hand if you need help.
Tell me when you start programming it, we can work together.
If you didn't have time, i will try soon to modify pytables code with 
your rigths.
Thanks a lot for your work.
Regards,
Philippe Collet