Le 28/04/2012 04:52, Benoît Minisini a écrit : > Le 28/04/2012 01:24, Jussi Lahtinen a écrit : >> At least the problem is unrelated to sin and cos... >> >> ? format(0.47942553860420300027 ^ 2 - >> 0.22984884706593014129,"#.######################") >> - .0000000000000012212453 >> >> ? format(0.47942553860420300027 ^ 2.0 - 0.22984884706593014129 >> ,"#.######################") >> - .0000000000000011379786 >> >> >> Jussi >> >> > > Hi, > > OK, I found the bug. > > The gambas floating point parser incorrectly took into account the > leading zero decimal digits. > > In other words 2.0 was computed as 20 * 10 ^ -1, 2.00 as 200 * 10 ^ -2. > Now it is just 2. > > Consequently, now 2.0 - 2 = 0, and cos(0.5) ^ 2.0 - cos(0.5) ^ 2 = 0. > > But cos(0.5) ^ 2 + sin(0.5) ^ 2 keeps being not exactly 1.0. Because the > gambas algorithm is not the same as the libc algorithm. In gambas 0.5 is > computed as 5 * 10 ^ -1, which does not give the exact binary > representation of 2 ^ -1. > > I will investigate... >
Hi, Precision bugs should be fixed now since revision #4688. ?cos(0.5)^2+sin(0.5)^2 1 ?0.5 - 1/2 0 Regards, -- Benoît Minisini ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
