function - 我应该使用 def、cdef 或 cpdef 定义我的 Cython 函数以获得最佳性能吗？

Question

假设我想要最佳性能，我如何知道在定义 Cython 函数时是使用 def、cdef 还是 cpdef？

Answer 1

如果您想要最佳性能，您应该知道如 this answer 中所述。一个相关的问题:

Once the function has been called there is no difference in the speed that the code inside a cdef and a def function runs at.

因此，为了获得最佳 Cython 性能，您应该 始终静态键入所有参数和变量 ，然后直觉上你会想使用 cdef ，但有一些注意事项我构建了下面的流程图(也基于前面提到的答案):



此外，请注意:

cpdef functions cause Cython to generate a cdef function (that allows a quick function call from Cython) and a def function (which allows you to call it from Python). Interally the def function just calls the cdef function.

...以及来自 Cython 文档:

This exploits early binding so that cpdef functions may be as fast as possible when using C fundamental types (by using cdef). cpdef functions use dynamic binding when passed Python objects and this might much slower, perhaps as slow as def declared functions.

还有一个 case-specific benchmark in the Cython documentation (经常从 Python 调用该函数)产生以下结果: