Dag Sverre Seljebotn skrev: > a) Is the cast to numpy.npy_intp really needed? I'm pretty sure shape is > > defined as numpy.npy_intp*.
I don't know Cython internals in detail but you do, I so take your word for it. I thought shape was a tuple of Python ints. > b) If you want higher performance with contiguous arrays (which occur a > lot as inplace=False is default I guess) you can do > > np.ndarray[T, ndim=1, mode="c"] > > to tell the compiler the array is contiguous. That doubles the number of > function instances though... Thanks. I could either double the number of specialized select functions, or I could make a local copy using numpy.ascontiguousarray in the select function. Quickselect touch the discontiguous array on average 2*n times, whereas numpy.ascontiguousarray touch the discontiguous array n times (but in orderly). Then there is the question of cache use: Contiguous arrays are the more friendly case, and numpy.ascontiguousarray is more friendly than quickselect. Also if quickselect is not done inplace (the common case for medians), we always have contigous arrays, so mode="c" is almost always wanted. And when quickselect is done inplace, we usually have a contiguous input. This is also why I used a C pointer instead of your buffer syntax in the first version. Then I changed my mind, not sure why. So I'll try with a local copy first then. I don't think we want close to a megabyte of Cython generated gibberish C just for the median. Sturla Molden _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
