Tim Peters <t...@python.org> added the comment:
I assumed Mark would tell us what's up with the arange() oddity, so let's see whether he does. There is no truly good way to generate "evenly spaced" binary floats using a non-representable conceptual decimal delta. The dumbass ;-) way doesn't show a discrepancy in pure Python: >>> num = ne = no = 0 >>> d = 0.001 >>> while num < 1.0: ... digit = int(round(num, 1) * 10) ... if digit & 1: ... no += 1 ... else: ... ne += 1 ... num += d >>> ne, no (500, 500) However, a somewhat less naive way does show a discrepancy, but less so than what arange() apparently does: >>> ne = no = 0 >>> for i in range(1000): ... digit = int(round(i * d, 1) * 10) ... if digit & 1: ... no += 1 ... else: ... ne += 1 >>> ne, no (501, 499) I assume that's because of the specific nearest/even behavior I already showed for multipliers i=250 and i=750. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue41198> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
