Citi, Luca skrev: > That is exactly why numexpr is faster in these cases. > I hope one day numpy will be able to perform such > optimizations. > I think it is going to require lazy evaluation. Whenever possible, an operator would just return a symbolic representation of the operation. This would gradually build up a tree of operators and buffers. When someone tries to read the data from an array, the buffer is created on-demand by flushing procratinated expressions. One must be sure that the buffers referenced in an incomplete expression never change. This would be easiest to ensure with immutable buffers. Numexpr is the kind of back-end a system like this would require. But a lot of the code in numexpr can be omitted because Python creates the parse tree; we would not need the expression parser in numexpr as frontend. Well... this plan is gradually getting closer to a specialized SciPy JIT-compiler. I would be fun to make if I could find time for it.
Sturla Molden _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
