Problems installing Parallel HDF5 on IBM Regatta (with AIX5)

When running configure and then make, errors similar to the following come up:

Macro name H5_PACKAGE_NAME cannot be redefined.
"H5_PACKAGE_NAME" is defined on line 312 of ../../src/H5pubconf.h.
Macro name H5_PACKAGE_STRING cannot be redefined.
... etc ...

This indicates that the HDF5 library was being built with the wrong C compiler that does not support MPI. Follow the instructions in the ./release_docs/INSTALL_parallel file, under the "IBM SP" section. Though it is geared towards a particular IBM installation, it does applies to the Regatta. The only exception is that you probably don't do the:

 setenv LLNL_COMPILE_SINGLE_THREADED TRUE

On the other hand, IBM has hundreds of environment variables and various compilers. Each site has various individual settings. Therefore, you should first try to compile and run some simple MPI-IO programs, both C and Fortran90, with the compilers,  mpcc_r and mpxlf_r, respectively. Once you get your MPI parallel environment set up, you can proceed with the instructions mentioned above.