[PD] maximum "control rate" in Pd

IOhannes m zmölnig zmoelnig at iem.at
Fri Mar 13 15:06:38 CET 2015

On 03/12/2015 10:11 PM, Roman Haefeli wrote:
> On Don, 2015-03-12 at 21:16 +0100, Cyrille Henry wrote:
>> for the simple answer, i would say that :
>> -from inside a patch, pd clock accuracy is "infinite"
> That is actually what I meant when I said it was limited by the
> precision of the floating point format being used.

actually time stamps in Pd do not use "Pd's native number type" (t_float
aka single precision float in almost all cases), but "double".

so clock accuracy is really very high.

otoh, finding a single number (like 1.4013e-45) for the clock tick
accuracy is a misconception, as the timestamps are really "absolute
timestamps" (in relation to Pd's start-time which is set to "0").
so the clock resolution gets worse the longer you run Pd.

think of the good ol' example if a patch-implemented [counter]
implemented, that stops incrementing by 1 at 10000000 or so; otoh if
your numbers stay small, you can increment by (say) 1e-6; the same holds
true for the timestamps: far in the future, the time-stamp resolution
will be e.g. 1 second or worse; luckily, using double precision, this
will be FAR in the future.


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