In <7x4otsux7f....@ruckus.brouhaha.com> Paul Rubin <http://phr...@nospam.invalid> writes:
>kj <no.em...@please.post> writes: >> sense = cmp(func(hi), func(lo)) >> assert sense != 0, "func is not strictly monotonic in [lo, hi]" >bisection search usually just requires the function to be continuous >and to have its value cross the target somewhere between the endpoints, >not be monotonic. Try the algorithm I posted with lo = -pi/4, hi = 2*pi, func = cos, target = -1, and see what you get... >> I regard the very special case of func(hi)==func(lo)==target as >> pathological (analogous to the fact that a stopped watch is "exactly >> right" twice a day), and not one I care to support. >I do think you should support that case, under the "do 'nothing' >gracefully" principle. You keep missing the point that this is an *internal* *helper* *convenience* function, meant to abstract away common logic from a handful of places and thus eliminate some code repetition within a module. It is *not* a library function intended to be called from elsewhere. So talk of "supporting" anything is besides the point. Any internal use of this function that applies it to a non-strictly-monotonic function is, by assumption, an error. kj -- http://mail.python.org/mailman/listinfo/python-list
