AD Code Generation

The AD Code of SHEMAT-Suite comprises the differentiated code routines, which are required when compiling in ad-mode for inverse simulations. The AD code needs to be updated when developments and changes were made in SHEMAT-Suite routines.

Some AD files were generated manually. They are in folders /inverse/g_tap for AD-forward-mode and /inverse/ad_tap for AD-reverse-mode. For example, the routine for arrays.f90 is derivated manually. Note that these AD-files have to be adapted manually, if any changes are made in the respective forward routines. E.g. if a new array is introduced in arrays.f90 it has to be added in /inverse/g_tap/g_arrays.f90, too!

Most of the AD routines are generated automatically by the TAPENADE automatic differentiation engine. This automatic generation is steered by the cmake file cmake/AD.cmake. User directories and property modules which shall be differentiated are defined in cmake/Sources.cmake.

The automatic AD code generation with TAPENADE is described in the following paragraph. Note that some manual adaptions might still be necessary at the end.

Generating automatic AD code:

• Prerequisites:

  Get a license for the TAPENADE software (free academic usage upon request), then download and unpack it. Then add its path to the PATH environment variable (e.g. /home/Tapenade/tapenade_3.14/bin).

  Python 2 is required for preprocessing scripts.

• Execute the AD-generation shell scipts available at https://git.rwth-aachen.de/SHEMAT-Suite/shemat-suite_scripts/-/tree/master/shell: generate-ad-head.sh for head-based AD-code generation, generate-ad-pres.sh for pressure-based AD-code generation, generate-ad-rm-head.sh for head-based reverse-mode AD-code generation, and generate-ad-rm-pres.sh for pressure-based reverse-mode AD-code generation.

  OR:

• Make a build-folder in the SHEMAT-Suite code directory:

mkdir build_ad
cd build_ad

• cmake with desired flags and options:

cmake -DPROPS=bas -DUSER=none -Dphys_base=head ..

• make ad-forward code:

make tap_tlm_clean
make tap_tlm

• make ad-reverse code:

make tap_adm_clean
make tap_adm

Note that the procedure has to be repeated for the pressure-based code (cmake with -Dphys_base=pres) in order to obtain the full AD code.