yt-project/yt

Faster particle depositions

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#2,281 opened on Jun 19, 2019

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enhancementhelp wantedindex: octreenew contributor friendlyperformance

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Description

In some AMR codes (such as RAMSES) the particles are read by yt in the order they appear in memory. This means that consecutive particles are likely to reside in the same oct (or in neighboring octs).

Using this, we could easily optimize the particle deposition scheme, so that when deposing a bunch of particles from the same oct, only one tree traversal is required.

This could either be done in particle_deposity.pyx https://github.com/yt-project/yt/blob/95f6c5dd1d06cb088f9369a15d478d6824090663/yt/geometry/particle_deposit.pyx#L89 or in the get method of the OctreeContainer object https://github.com/yt-project/yt/blob/a209a67f2977571925bc297739003254130ef9b3/yt/geometry/oct_container.pyx#L203

For instance, one could check that two consecutive particles leave in the same cell.

Contributor guide

Research direction
Investigate the particle deposition loop in particle deposit.pyx and the OctreeContainer get method in oct container.pyx. Focus on detecting when consecutive particles are in the same or neighboring octs to reduce tree traversals.
Tech stack
python
Domain
backend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Python
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60