Reimplement managed raster class in C++ #1597
Conversation
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@phargogh this is finally ready for re-review! The biggest change is I figured out how to implement the iterators properly, so they can be iterated with the usual syntax, solving the issues with tracking/incrementing values properly. |
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Thanks @emlys , this looks good to me! I had a couple of minor comments, and then I also wanted to confirm: what we have here in this PR looks to be intended for MFD routing, specifically, so is D8 routing to be added in a future PR?
| include_dirs = [numpy.get_include(), 'src/natcap/invest/managed_raster'] | ||
| if platform.system() == 'Windows': | ||
| compiler_args = ['/std:c++20'] | ||
| library_dirs = [f'{os.environ["CONDA_PREFIX"]}/Library/lib'] | ||
| include_dirs.append(f'{os.environ["CONDA_PREFIX"]}/Library/include') | ||
| else: | ||
| library_dirs = [] | ||
| compiler_args = [] | ||
| compiler_and_linker_args = ['-stdlib=libc++', '-std=c++20'] | ||
| library_dirs = [subprocess.run( | ||
| ['gdal-config', '--libs'], capture_output=True, text=True | ||
| ).stdout.split()[0][2:]] # get the first argument which is the library path |
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Since we are now building directly against gdal, should we add the new build dependency to pyproject.toml?
| else: | ||
| library_dirs = [] | ||
| compiler_args = [] | ||
| compiler_and_linker_args = ['-stdlib=libc++', '-std=c++20'] |
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Is C++20 truly the minimum language version required? I don't think this should be a huge deal since compilers seem to pretty rapidly adopt the new standards, so I think this is mostly a question of curiosity.
| ManagedFlowDirRaster(char* raster_path, int band_id, bool write_mode) | ||
| : ManagedRaster(raster_path, band_id, write_mode) // Call the superclass constructor in the subclass' initialization list. | ||
| { | ||
| // do something with bar | ||
| } |
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Is the plan to still do something in this constructor?
Description
This PR reimplements the
ManagedRasterclass in C++ for better performance. Tested withsdr.calculate_sediment_depositionand the SDR sample data, it's now just slightly faster than the original implementation onmain(0.59 vs 0.61 seconds), whereas the python implementation onfeature/routing-refactortakes nearly twice as long.I'm a beginner at C++ so I'm sure I'm not always using the right conventions or design patterns, but this seems like an okay starting point. I took some guidance from the Google C++ style guide. Ignoring some guidelines that don't seem to make sense in this context. For instance, I have all the code in a header file because splitting it out into
ManagedRaster.handManagedRaster.cppsignificantly slowed it down.Happy to discuss and walk through this PR on a zoom call as well.
Checklist