Re: [Pytables-users] subarray extraction and update

[Bernard K. <ber...@be...>]

Dear Antonio,

In hdf5 you can define progressively a selected region (adding elements=20
one by one) by use of either "H5Sselect=5Felements" with H5S=5FSELECT=5FAPP=
END=20
or "H5Sselect=5Fhyperslab" with H5S=5FSELECT=5FOR. Then you can read or wri=
te=20
the selected elements at once with "H5Dread" or "H5Dwrite".

Is there a function in pytables that use this functionality ? How would=20
you do to extract a submatrix in pytables ?

Bernard||

Antonio Valentino wrote:

>Alle 11:36, luned=EC 25 luglio 2005, Bernard KAPLAN ha scritto:
> =20
>
>>Dear all,
>>   =20
>>
>
>hi Bernard
>
>[...]
>
> =20
>
>>x=3Darray([1,2,5,8])   # row index
>>y=3Darray([0,3,7])   # column index
>>a=3Ddata[x,y]   # returns an array of size [4,3], 'data' is a pytables 2-d
>>array
>>data[x,y]=3D0   # set the submatrix defined by x rows and y columns to 0
>>data[x,y]=3Drand([4,3])  # update of a submatrix
>>data[x,y]=3Ddata2[x,y]   # copy of a submatrix from one array into another
>>   =20
>>
>
>I think that what you are asking for can't be done in an "elegant" way.
>HDF5 supports hyperslabs selection that is powerfull and elegant but it=20
>requires reqular spacing in the selection, see=20
>
>http://hdf.ncsa.uiuc.edu/HDF5/doc/RM=5FH5S.html#Dataspace-SelectHyperslab
>
>In order to use hyperslabs you have to be able to express the sub-matrix=20
>selection in terms of "start, stride, count, and block".
>It seems to me that it is not your case.
>
> =20
>
>>Sincerely,
>>
>>Bernard KAPLAN
>>
>>
>>
>>-------------------------------------------------------
>>SF.Net email is sponsored by: Discover Easy Linux Migration Strategies
>>from IBM. Find simple to follow Roadmaps, straightforward articles,
>>informative Webcasts and more! Get everything you need to get up to
>>speed, fast. http://ads.osdn.com/?ad=5Fid=3D7477&alloc=5Fid=3D16492&op=3D=
click
>>=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=
=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F
>>Pytables-users mailing list
>>Pyt...@li...
>>https://lists.sourceforge.net/lists/listinfo/pytables-users
>>   =20
>>
>
>ciao
>
> =20
>