PDI usage

After Installation of PDI step, PDI must be used in the application, that is written either in C/C++, Fortran or Pyhton.

Preparing the environment

PDI was installed in default location

The library and plugins should be found without any problem, but a good approach is to make sure that all environment variables are set correctly. To do this, there are 3 options:

1. source pdirun - sets up current environment variables
2. pdirun bash - creates new shell with environment variables set up
3. pdirun command - runs a command with all environment variables set up

To have the environment always prepared for using PDI, the first option (source pdirun) can be added to ~/.bash_profile file. After that, any new shell will have environment variables set up.

PDI was installed in custom location

To prepare environment in this case there are 3 options:

1. source PDI_path/share/pdi/env.bash - sets up current environment variables
2. PDI_path/bin/pdirun bash - creates new shell with environment variables set up
3. PDI_path/bin/pdirun command - runs a command with all environment variables set up

where PDI_path is the path where PDI was installed.

To have the environment always prepared for using PDI, the first option (source PDI_path/share/pdi/env.bash) can be added to ~/.bash_profile file. After that, any new shell will have environment variables set up.

Compilation of an application

If source files (of application that uses PDI) and specification tree file are ready, the compilation step can be made. For C make sure that source files that use PDI API are including pdi.h header file. For Fortran make sure that source files that use PDI API are using PDI module file (USE PDI).

Compiling by hand

To compile application, linker flag -lpdi must be used. For C it would look like this:

gcc source_files.c -o exec_file -lpdi

For Fortran it would look like this:

gfortran source_files.f90 -o exec_file -lpdi

Compiling with cmake

If source files (of application that uses PDI) and specification tree file are ready, the compilation step can be made.

C/C++ compilation

To compile C/C++ application, cmake must find C component from PDI package. Then the PDI::PDI_C library must be linked to the target:

find_package(PDI REQUIRED COMPONENTS C)
 
add_executable(exec_file source_files.c)
target_link_libraries(exec_file PDI::PDI_C)

Fortran compilation

To compile Fortran application, cmake must find f90 component from PDI package. Then the PDI::PDI_f90 library must be linked to the target:

find_package(PDI REQUIRED COMPONENTS f90)
 
add_executable(exec_file source_files.c)
target_link_libraries(exec_file PDI::PDI_f90)

Running an application

PDI is a shared library. That means that all environment variables must be set not only on compilation, but also when running the program.

Every used plugin in application needs to be found by PDI. It will search for plugins in 4 steps (it will use the first plugin found):

1. PDI_PLUGIN_PATH environment variable that is colon separated list with paths,
2. plugin_path subtree in specification tree: plugin_path,
3. Relative path of used PDI shared object libpdi.so,
4. LD_LIBRARY_PATH environment variable that is colon separated list.