On Thu, 22 Dec 2011 07:40:19 -0600 Jeff Epler <jep...@unpythonic.net> wrote:
> I understand the rest, but what's the + 0.1 part doing? The +0.1 is to protect against floating point inaccuracies. Imagine the ceil() operation yields a 200.0, for example. But due to floating point inaccuracies it's actually represented as 199.9999999999999. So the (implicit) int cast would (tail)-cast it to 199, instead of the correct 200. The +0.1 avoids that. > fwiw the code was added to fix this bug: > http://sourceforge.net/tracker/?func=detail&aid=2478266&group_id=6744&atid=106744 > > I think that ceil, round or (implicit in integer division) floor are all > OK as fixes to the original problem, so I'd be tempted to just drop the > useless ceil() call instead and leave the behavior unchanged. Ok, well. I'm don't really understand the code good enough to have an opinion on this, but changing the code to this: servo_mult = traj_period_nsec / nsec; should maintain the current semantics, but avoid the floating point stuff. Please also note that some older compilers are confused by that floating point stuff there and throw internal errors. (That's how I got attracted to that code). So it should be fixed either way. -- Greetings, Michael. ------------------------------------------------------------------------------ Write once. Port to many. Get the SDK and tools to simplify cross-platform app development. Create new or port existing apps to sell to consumers worldwide. Explore the Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join http://p.sf.net/sfu/intel-appdev _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
