[netcdfgroup] NetCDF4/HDF5 comparison

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• Subject: [netcdfgroup] NetCDF4/HDF5 comparison
• From: "Shibaev, Sergei" <Sergei.Shibaev@xxxxxxxxxxxx>
• Date: Fri, 25 Sep 2009 09:16:34 +0100

Hi All interested in API performance,
 
I have compared access time to NetCDF4 file using NetCDF and HDF API.
Please find attached source code of two simple test programs; both do
exactly the same, measure full time of: open data file, search for
specified data item (integer-only ADC data) , read it into memory, and
close the file.
Here are results for two different files; both contain compressed data.
The files are structured; data items are in groups.
 
1) Large item (1 MB), simple file (40 items).
API              Read time
HDF             149 ms
NetCDF        192 ms
Comment: mostly uncompressing time
 
2) Small item (40 kB), complex file (> 3000 items).
API              Read time
HDF             19 ms
NetCDF        2123 ms
Comment: It seems that NetCDF API builds full file structure when HDF
API does only what is requested.
 
Regards,
Sergei
 


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Attachment: n4read.cpp
Description: n4read.cpp

Attachment: h5read.cpp
Description: h5read.cpp

• References:
  • [netcdfgroup] New release of Objective-C wrapper for netCDF
    • From: Mark Tracy