Hi Norman, >-----Original Message----- >From: [email protected] [mailto:hdf-forum- >[email protected]] On Behalf Of Williams, Norman K >Sent: Tuesday, May 03, 2011 12:21 PM >To: HDF Users Discussion List >Subject: Re: [Hdf-forum] How does chunked reading/writing interact with >setting hyperslabs in datasets? > >OK. > > >I'm not entirely clear how to coordinate different memory and disk >footprints, particularly when using the C++ interface. > >The steps I know about: > >1. Open the file >2. Open the DataSet. >3. Obtain the DataSpace from the Dataset. >4. Select a hyperslab to read data into a voxel buffer. > >I select a hyperslab from the dataset to read based on the image region >specified by the user. It's a little more complicated than that in ITK, >but that summarizes the process. > >At what stage in the process do I specify a different in-memory dataspace? > And how do I specify it's position in the larger on-disk dataspace? > >If there's example code in the manual, just point me there. > The C++ examples can be found here http://www.hdfgroup.org/HDF5/doc/cpplus_RM/examples.html, but you're probably already aware of that, so my next suggestion is to look at the C examples for appropriate pattern.
> >On 5/3/11 10:56 AM, "Quincey Koziol" <[email protected]> wrote: > >>Hi Kent, >> >>On May 3, 2011, at 10:16 AM, Williams, Norman K wrote: >> >>> I am using the H5Sselect_hyperslab method for both reading and writing >>> already. Additionally when I write out an image, I 'chunk' the output >>>and >>> compress it. >>> >>> >>> The question I have is what I can do to minimize the memory footprint. >>> Based on my reading in the documentation, the Hyperslab interface >>>actually >>> scatters/gathers to/from an in-memory dataset, leading me to believe the >>> entire dataset will be allocated in system memory. >>> >>> So the question is how would I use HDF5 in such a way as to minimize the >>> memory footprint in this context? >> >> You are allowed to create a memory dataspace that is different from >>the dataset's dataspace in the file. That will allow you to tune the >>memory footprint. >> > > > >________________________________ >Notice: This UI Health Care e-mail (including attachments) is covered by >the Electronic Communications Privacy Act, 18 U.S.C. 2510-2521, is >confidential and may be legally privileged. If you are not the intended >recipient, you are hereby notified that any retention, dissemination, >distribution, or copying of this communication is strictly prohibited. >Please reply to the sender that you have received the message in error, >then delete it. Thank you. >________________________________ > >_______________________________________________ >Hdf-forum is for HDF software users discussion. >[email protected] >http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org > > >-- >Internal Virus Database is out-of-date. >Checked by AVG. >Version: 7.5.549 / Virus Database: 270.9.0/1778 - Release Date: 11/9/2008 >2:14 PM _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
