Re: Using "delay until" in real-time

[Ray Blaak <blaak@infomatch.com>]

Ted Dennison <dennison@telepath.com> writes:
> I see a couple of problems with this.
[...]
>    o  Iteration_Count * Iteration_Hz is no different mathematicly from
> adding Iteration_Hz to Start_Time Iteration_Count times, which is what I
> was doing. You'd still get the same compounding round-off error.

Would it? It might be the same mathematically, but computers don't do Real
arithmetic mathematically, only approximately.

Consider floating arithmetic accurate to 2 decimal places:

 Hz = 60, Inc = 1/Hz = 1.67

Adding incrementally twice:

 Inc + Inc = 3.34

Multiplying 2 iterations from a start time of zero:

 (1 + 1) / 60 = 3.33

The trick is to divide the total count so far by your Hz, not multiply by a
precomputed 1/Hz.
-- 
Cheers,                                        The Rhythm is around me,
                                               The Rhythm has control.
Ray Blaak                                      The Rhythm is inside me,
blaak@infomatch.com                            The Rhythm has my soul.