[GRASS-dev] raster module parallelization with openmp

[Markus Metz]

Hi,

I have implemented parallelization with openmp in r.proj. On a
quad-core system this gives me a 50% speed increase (twice as fast)
compared to the regular single thread version, tested with all
interpolation methods. The speed increase is consistent and the
results are identical to single thread calculation. I am not sure if
concurrent read access of several threads to the same file used as
temporary cache can cause problems for a large number of threads or
input files substantially larger than available RAM.

Some other raster modules that could be parallelized in a similat
fashion would be v.rectify, r.resamp.interp, r.neighbors, maybe
r.resamp.filter and others.

Markus M