Scot Breitenfeld
9b77f784f7
Adds HDF5Examples/C/H5PAR/ph5_comm_split.c, showing parallel HDF5 use on a communicator produced by MPI_Comm_split rather than on MPI_COMM_WORLD. The example splits MPI_COMM_WORLD by rank parity. The even ranks form a writer group that collectively creates a dataset with one row per writer rank, then reopens the file read-only on the same sub-communicator and verifies what it wrote. The odd ranks stand in for a group with other responsibilities and make no HDF5 calls at all. The comments cover the two rules this pattern depends on: MPI_Comm_split is collective over the parent communicator, so every rank must call it even if it never opens the file; and once a file is opened with a FAPL carrying a sub-communicator, every collective HDF5 call on that file is collective over that sub-communicator alone. The example runs with any number of MPI ranks.
HDF5 Examples
Please refer to the Using_CMake.txt file for CMake instructions.
Note that this HDF5Examples directory structure is also provided as a stand-alone project distributed with library binaries as well as compiled and tested during a HDF5 Library build.
This repository contains a high-performance library's example code that demonstrate the HDF5® data model API. The HDF5® data model has been adopted across many industries and this implementation has become a de facto data management standard in science, engineering, and research communities worldwide.
The HDF Group is the developer, maintainer, and steward of HDF5 software. Find more information about The HDF Group, the HDF5 Community, and other HDF5 software projects, tools, and services at The HDF Group's website.
We suggest using the presets method with CMake for building the examples. However, if you prefer to use the h5cc pkg-config wrappers, you can use the following commands to build the examples:
export HDF5_HOME="hdf5 installation root"
export PKG_CONFIG_PATH="$HDF5_HOME/lib/pkgconfig"
export LD_LIBRARY_PATH="$HDF5_HOME/lib:$LD_LIBRARY_PATH"
export PATH="$HDF5_HOME/bin:$PATH"
Then, you can compile the examples with:
h5cc -o example1 example1.c
h5c++ -o example2 example2.cpp
h5fc -o example3 example3.f90
For Java examples with Maven integration, see the JAVA/README-MAVEN.md file for complete instructions on using the org.hdfgroup:hdf5-java-examples Maven artifact.
The test-pc.sh script can test the examples with the h5*cc pkg-config wrappers with: cd <path to examples> export HDF5_HOME="hdf5 installation root"; sh ./test-pc.sh <path to examples> <path to build dir> . Notice that period (.) at the end of the command is important, it tells the script to use the current directory as the source directory.
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