Subtask speedup
For now, compile with CFLAGS=-DONLY_SUBTASKS added to the configuration line.
This introduces significantly faster neighbour finding in particle distributions with strong density gradients. For instance planetary applications or problematic feedback-disturbed galaxies.
Changes:
- Add the brute-force density checks to the planetary scheme (not just sphenix)
- Rewrite the recursion logic in the hydro and stars sub-task:
- The interaction functions have extra parameters to optionally consider particles only between 0.5 * width and width
- The subtask recursion now continues to lower level if we reach a level where h is too large. From that level on, we will just use the feature of only considering particles in the appropriate range of h.
- When recursing, only the h_max of active particles is considered, not all particles.
Notes:
- We will consider c7adb289 separately.
- In a second phase, I'll remove entirely the self + pair tasks and keep only the subs.
Todo:
- Verify RT isn't broken
- Verify MPI runs are happy.
- Port changes to the other hydro schemes.
- Handle particles drifting out of their cells.
Fixes #688 (closed).