Re: [Pytables-users] User block in HDF5 files

[Anthony S. <sc...@gm...>]

Thanks for bringing this to our attention Brad!

On Tue, Jan 24, 2012 at 9:50 AM, Brad Buran <bb...@cn...> wrote:

> Created at  https://github.com/PyTables/PyTables/issues/123.  If I get a
> chance, I'll see if I can work out how to add this functionality but it
> won't be for a few weeks.
>
> Thanks!
> Brad
>
>
> On Thu, Jan 19, 2012 at 2:10 PM, Anthony Scopatz <sc...@gm...>wrote:
>
>> On Thu, Jan 19, 2012 at 1:02 PM, Antonio Valentino <
>> ant...@ti...> wrote:
>>
>>> Hi Brad,
>>>
>>> Il 19/01/2012 04:13, Brad Buran ha scritto:
>>> > Hi Antonio:
>>> >
>>> > The user block I am referring to is a region at the beginning of the
>>> > file that is reserved for user metadata.  I pasted the description
>>> > from the HDF5 documentation below
>>> > (http://www.hdfgroup.org/HDF5/doc1.6/UG/08_TheFile.html).  I believe
>>> > H5Py added this feature
>>> > (http://code.google.com/p/h5py/source/detail?r=8a3010d07e14); however,
>>> > I don't see a similar way to do this via PyTables.  I suppose I could
>>> > use h5py to create a blank HDF5 file with the required user block then
>>> > reopen it in PyTables, however, I'd like to minimize code dependencies
>>> > and everything I've written is built around PyTables rather than h5py.
>>> >
>>>
>>> Sorry, for the misunderstanding, I was not aware of this feature.
>>>
>>> Please file a feature request on https://github.com/PyTables/PyTables
>>>
>>
>> Yes, I agree that this should be an added feature.  It seems like it
>> should be a
>> keyword argument to the File() constructor.
>>
>> As Antonio said, please open an issue for this.  On the other hand if you
>> want to
>> try your hand implementing it, we'll review any pull request you send our
>> way.
>>
>> Be Well
>> Anthony
>>
>>
>>>
>>>
>>> best regards
>>>
>>>
>>> > Thanks!
>>> > Brad
>>> >
>>> > Documentation from HDF5:
>>> >
>>> > User-block size
>>> >              herr_t H5Pset_userblock (hid_t plist, hsize_t size)
>>> >              herr_t H5Pget_userblock (hid_t plist, hsize_t *size)
>>> >
>>> >     The user-block is a fixed-length block of data located at the
>>> > beginning of the file and which is ignored by the HDF5 library. This
>>> > block is specifically set aside for any data or information that
>>> > developers determine to be useful to their application but that will
>>> > not be used by the HDF5 library. The size of the user-block is defined
>>> > in bytes and may be set to any power of two, with a minimum size of
>>> > 512 bytes (i.e. 512, 1024, 2048, etc). This property is set with
>>> > H5Pset_userblock and queried via H5Pget_userblock.
>>> >
>>> >     For example, if an application was thought to reqire a 4K
>>> > user-block, that could be set with the following function call:
>>> >              status = H5Pset_userblock(fcpl_id, 4096)
>>> >     The property list could later be queried with
>>> >              status = H5Pget_userblock(fcpl_id, size)
>>> >     and the value 4096 would be returned in the parameter size.
>>> >
>>> >
>>> > On Wed, Jan 18, 2012 at 4:52 PM, Antonio Valentino
>>> > <ant...@ti...> wrote:
>>> >> Hi Brad,
>>> >>
>>> >> Il 18/01/2012 21:49, Brad Buran ha scritto:
>>> >>> Is there a way to set the size of the user block when creating a file
>>> >>> in PyTables?  This would be useful for using PyTables to generate
>>> >>> Matlab 7.3 compatible files.
>>> >>>
>>> >>> Brad
>>> >>
>>> >> Try to use CArrays and set the chunkshape explicitly
>>> >>
>>> >>
>>> http://pytables.github.com/usersguide/libref.html#tables.File.createCArray
>>> >>
>>> >> Does it answers your question?
>>> >>
>>> >>
>>> >> best regards
>>> >>
>>> >>
>>> >> --
>>> >> Antonio Valentino
>>> >>
>>>
>>> --
>>> Antonio Valentino
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> Keep Your Developer Skills Current with LearnDevNow!
>>> The most comprehensive online learning library for Microsoft developers
>>> is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
>>> Metro Style Apps, more. Free future releases when you subscribe now!
>>> http://p.sf.net/sfu/learndevnow-d2d
>>> _______________________________________________
>>> Pytables-users mailing list
>>> Pyt...@li...
>>> https://lists.sourceforge.net/lists/listinfo/pytables-users
>>>
>>
>>
>>
>> ------------------------------------------------------------------------------
>> Keep Your Developer Skills Current with LearnDevNow!
>> The most comprehensive online learning library for Microsoft developers
>> is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
>> Metro Style Apps, more. Free future releases when you subscribe now!
>> http://p.sf.net/sfu/learndevnow-d2d
>> _______________________________________________
>> Pytables-users mailing list
>> Pyt...@li...
>> https://lists.sourceforge.net/lists/listinfo/pytables-users
>>
>>
>
>
> ------------------------------------------------------------------------------
> Keep Your Developer Skills Current with LearnDevNow!
> The most comprehensive online learning library for Microsoft developers
> is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
> Metro Style Apps, more. Free future releases when you subscribe now!
> http://p.sf.net/sfu/learndevnow-d2d
> _______________________________________________
> Pytables-users mailing list
> Pyt...@li...
> https://lists.sourceforge.net/lists/listinfo/pytables-users
>
>