I just did a long test from 1 - 10000 and I noticed that every time the number was increased with one bit (starting with 2048, then 4096, then 8192) behaviour changes. You were right, my bad.
Makes me wonder though, what's the point of a bankers' algorithm if .005 can never be reached, only approached? :) This unpredictable rounding behaviour is a real b*tch, but what can you do :) Ron "Sara Golemon" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > > I understood that round() is using the so called Bankers' round algorithm. > > But I notice it's inconsistent. The banker's algorithm is magically > > activated only for numbers beyond 2047.0. Before 2047, the "classic" > > 5-is-rounded-up method is used. > > > > Floating point numbers are........ imprecise. > > What you see as 2047.005, the computer might see as > 2047.0049999999999999123869128 or perhaps as 2047.005000000000000012396291 > > When I only care about a certain accuracy (such as with monetary amounts) I > 'solve' this quirk of the CPU by adding a miniscule fudge factor: > > round($someval + 0.000000001, 2) > > PHP doesn't do this automatically because sometimes a plus-fudge is > appropriate, sometimes a negative-fudge is better. > > -Sara -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
