On 7/18/06, Cyrille Dunant <[EMAIL PROTECTED]> wrote:
> > Yeah, Kai already emailed me with a grep. I, unfortently, am not at my > house, and I can't work on glob2 for atleast three weeks while my > family moves. Worse yet, me might have to get modem-internet in our > next house. Anyway, all of these usages are independant casts, so in > my case, atleast the same CPU will give the same results every time. no. Not even with the same compiler. The bits at the end of the mantissa are _random_ they depend on the system state, the weather, and the bugs in your hardware, and the manufacturer's breakfeast when they were built.
So why do you think that a compiler would intentionally leave bits unitialized in the mantissa when it could initialize them and add better determinism? All of my usages of float are casts, temporaries, un-accumulated values from integers. Theres no reason for the compiler to leave bits unitialized when its being provided the same deterministic value as input. Float insafety is caused mainly by accumulated-error and having a different exponent and mantissa representing the same value ( 50 * 0.1 or 5 * 1.0 ). If your willing to explain yourself, then good, but I see no reason for the compiler to leave unitialized bits inside a value thats being initialized.
Do _not_ _ever_ depend on doubles for bit perfect reproducibility. > I'll fix this as soon as I have time. Sorry everyone, my mistake. CU -- CFD _______________________________________________ glob2-devel mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/glob2-devel
-- Start and finish, Bradley Arsenault _______________________________________________ glob2-devel mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/glob2-devel
