[GRASS-dev] [SoC] GSoC 2021 - Parallelization of raster modules for GRASS GIS

[Aaron Saw Min Sern]

Hi everyone,

Week 6 has concluded and here's my report for this week.

1) What did I get done this week?
r.neighbors
The main goal that I have accomplished is to do a complete rework of the r.neighbors implementation (PR: https://github.com/OSGeo/grass/pull/1724). A benchmark script is ready under 'benchmark' directory for users to test the performance on their local machine. The performance is comparable to the previous implementation that make use of temporary files as buffer (on SSD) instead of memory. The result of the benchmarking on my local machine (12 cores) is as follows:

[cid:78740075-d760-48f5-aff3-98a5a38cdc0f]

r.mfilter
There are issues pointed out when working on raster files > 2GB (PR: https://github.com/OSGeo/grass/pull/1708). This is promptly addressed with commit (4caa96), and the cause is due to overflow from multiplication. This PR is ready, and a benchmark script is provided as well for local benchmarking.

2) What do I plan on doing next week?

  *   Introduce an environment variable that overwrites the default nprocs parameter which is currently 1. This is so that the users do not need to add nprocs parameter explicitly.
  *   Implement r.resamp.filter/r.resamp.interp parallelization

3) Am I blocked on anything?
No major issues.

Thanks,
Aaron
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