1. © 2007 The MathWorks, Inc. ® ® Using HDF5 in MATLAB Jeff Mather The MathWorks HDF/HDF-EOS Workshop XI (Nov. 2007)

2. 2 ® ® What is MATLAB?  A high-level programming language.  An interactive design, exploration, and simulation environment.  A platform for performing diverse tasks in many disciplines:  Math and Optimization  Statistics and Data Analysis  Control System Design and Analysis  Signal Processing and Communications  Image Processing  Test & Measurement  Financial Modeling and Analysis  Application Deployment  Database Connectivity and Reporting  Distributed Computing

3. 3 ® ® MATLAB’s support for HDF products HDF4 (v4.2r1) HDF-EOS2 (v2.12v1.00) HDF5 (v1.6.5)

4. 4 ® ® A typical HDF5 function herr_t H5Dread(hid_t dataset_id, hid_t mem_type_id, hid_t mem_space_id, hid_t file_space_id, hid_t xfer_plist_id, void * buf ) success = H5Dread(dataset, H5T_STD_I32BE, H5S_ALL, H5S_ALL, H5P_DEFAULT, buffer);

5. 5 ® ® A typical HDF5 function herr_t H5Dread(hid_t dataset_id, hid_t mem_type_id, hid_t mem_space_id, hid_t file_space_id, hid_t xfer_plist_id, void * buf ) success = H5Dread(dataset, H5T_STD_I32BE, H5S_ALL, H5S_ALL, H5P_DEFAULT, buffer); (2) Note the frequent use of defined values and “constants.” (4) Note the appearance of output on the right-hand side. (3) Note the success value on the left-hand side. (1) Note the void*.

6. 6 ® ® A typical MATLAB function [N, X] = hist(DATA)  Multiple left-hand arguments.  Outputs on the left, inputs on the right.  Very weakly typed.

7. 7 ® ® Calling an HDF5 function in MATLAB C success = H5Dread(dataset, H5T_STD_I32BE, H5S_ALL, H5S_ALL, H5P_DEFAULT, buffer); MATLAB buffer = H5D.read(dataset, ‘H5T_STD_I32BE’, ‘H5S_ALL’, ‘H5S_ALL’, ‘H5P_DEFAULT’)

8. 8 ® ® Let’s look at examples in MATLAB…

9. 9 ® ® The H5ML interface H5ML.compare_values H5ML.get_constant_names H5ML.get_constant_value H5ML.get_function_names H5ML.get_mem_datatype H5ML.hoffset H5ML.sizeof + H5ML.id

10. 10 ® ® Getting help  To see what’s in a package: “ help H5D ”  For help on an HDF5 function: “ help H5D.read ”  To use the full power of HDF5, you need to understand the C or Fortran interface.  E-mail support@mathworks.com.support@mathworks.com