On Sat, Jun 21, 2008 at 18:45, Anne Archibald <[EMAIL PROTECTED]> wrote: > 2008/6/21 Robert Kern <[EMAIL PROTECTED]>: >> On Sat, Jun 21, 2008 at 17:08, Anne Archibald <[EMAIL PROTECTED]> wrote: >>> My suggestion is this: allow negative indices, accepting the cost in >>> tight loops. (If bounds checking is enabled, the cost will be >>> negligible anyway.) Provide a #pragma allowing the user to assert that >>> a certain piece of code uses no negative indices. >> >> Instead of a #pragma, you could rely on the type of the index. If it >> is unsigned, you can do the fast path; if it is signed, you need to >> check for and handle potential negatives. > > Cute! And then it's easy to make "for i in range(n)" produce unsigned > results with no effort on the part of the user.
Not entirely. You still need to declare "cdef unsigned int i". Cython does not translate the for loop into fast C unless if the variable has been declared. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
