This was a project done for INF7235. We chose to analyse and parallelize a part of the application SORTIE-ND, an individual forest simulator designed to study neighborhood processes. We worked on the 7.01 beta code for this project.

Since this is a proof of concept, we only implemented one change: we tried to parallelize the basic light behavior, since this is the most important and, for our test files, at least 50% of the computing time was used for this behavior. Most of the changes are there in one file: sortie_tbb/Core_Model/Behaviors/LightOrg.cpp, in the DoLightAssignments method.

Other modifications were mostly to be able to choose the method of parallelization and to remove some race conditions. For some of the light behaviors, the race conditions would require major changes to the code, so they were not corrected.

We used Intel Threading Building Blocks to parallelize the light behavior: three different approaches were tested: parallel_for (this required first putting all trees in a vector), parallel_pipeline and task groups.

We used the unit tests written by the devs to check our changes. At the moment it is only possible to run one test, running multiple tests causes problems with some static fields in the simulations.