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Are parts of NumPy and/or SciPy programmed in C/C++?
And how does the overhead of calling C from Python compare to the overhead of calling C from Java and/or C#?
I'm just wondering if Python is a better option than Java or C# for scientific apps.
If I look at the shootouts, Python loses by a huge margin. But I guess this is because they don't use 3rd-party libraries in those benchmarks.
Most of NumPy is in C, but a large portion of the C code is "boilerplate" to handle all the dirty details of the Python/C interface. I think the ratio C vs. Python is around 50/50 ATM for NumPy.
I am not too familiar with vm-based low-level details, but I believe the interface cost would be higher because of the restrictions put on the jvm and the .clr. One of the reason why numpy is often faster than similar environments is the memory representation and how arrays are shared/passed between functions. Whereas most environments (Matlab and R as well I believe) use Copy-On-Write to pass arrays between functions, NumPy use references. But doing so in e.g. the JVM would be hard (because of restrictions on how to use pointer, etc...). It is doable (an early port of NumPy for Jython exists), but I don't know how they solve this issue. Maybe C++/Cli would make this easier, but I have zero experience with that environment.
