Daniele, The Packet Table interface ends up creating a standard dataset that can be read just like any other dataset. But it does simplify setup and appending data.
In fact, at a code level, you must access it as a dataset (H5D) in order to do certain things... attributes & scales come to mind. S > -----Original Message----- > From: [email protected] [mailto:hdf-forum- > [email protected]] On Behalf Of Daniele Nicolodi > Sent: Thursday, August 18, 2011 4:28 PM > To: [email protected] > Subject: Re: [Hdf-forum] HDF5 file structure for data logging > > On 18/08/11 20:49, John Knutson wrote: > > In my own work, I use pre-sized datasets with compound types. Our > data > > are not homogeneous, so the compound types are pretty much required. > > The pre-sized datasets affords us the ability to actively index the > data > > on read and write, which is of particular value on the read-side > where > > knowing exactly where to find the data you want is highly valuable. > > > > If, on the other hand, you just need to store data that you're never > > going to do partial reads of, packet tables are easier to implement. > > Dear John, > > thank you very much for your hints. Partial reads and absolute > performances are not critical for my application. I think I'll give > packet tables a try. On the other hand, easily accessing the data from > Python and Matlab is a requirement. > > Are packet tables (or the underlying structures) accessible in an easy > way from Matlab? Python has the h5py library, which, if it is not > already capable of handling packet tables, should be not too difficult > to extend. > > A while back I investigated the kind of data structure used by > PyTables, > which offers the kind of functionality I'm interested in. From my > aproximative knowledge of HDF5, I understood that it uses a "custom" > version of HDF5 Tables which support chunked writes. However I need > compatibility with Matlab and the ability of writing those files from a > C library. How such a structure compares with packed tables? > > Thank you. Cheers, > -- > Daniele > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org This e-mail and any files transmitted with it may be proprietary and are intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error please notify the sender. Please note that any views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of ITT Corporation. The recipient should check this e-mail and any attachments for the presence of viruses. ITT accepts no liability for any damage caused by any virus transmitted by this e-mail. _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
