On Fri, Mar 4, 2011 at 12:30 PM, Jon Elson <el...@pico-systems.com> wrote:
> Igor Chudov wrote: > > > > Whils I kind of agree in general (I do numerical modeling too, for a > > living), here we are essentially comparing a == a and it fails. See my > > another post in this thread about GCC bug 323. > > > > My concern with doing what I am doing, is that if I wanted the knee to > move > > at glacial speed, it would shut off. > > But I know that I do not need it. > > > Well, when comparing two floating point numbers, the comparison only > shows that they are the same within the limits of the mantissa > representation in that floating point format. (Of course, a double has > a LOT of bits of mantissa....) > > But, anyway, you used 1E-7, so with 1000 servo cycles/second, that would > require moving slower than one inch every 1000 seconds to fool the > comparison. That is REALLY slow! Way below "glacial" speed. > > At 1000 cycles per second, 1E-7 amounts to 0.006 IPM. Really not very fast. And with the latest change made, where I update last value only if a move occurred, the servo would wake up even at "below glacial" speed. IOW, I think that I am all set in the best possible way. i ------------------------------------------------------------------------------ What You Don't Know About Data Connectivity CAN Hurt You This paper provides an overview of data connectivity, details its effect on application quality, and explores various alternative solutions. http://p.sf.net/sfu/progress-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
