[PD] strange bug [f], Pd 0.45.5

[Jonghyun Kim]

FYI: I used very fast metronome [metro 1] or [metro 0.1], so I think the
float value(allowed under 32bit) maximized so quickly.

On Mon, Oct 6, 2014 at 3:40 AM, Jonghyun Kim <agitato816 at gmail.com> wrote:

> Thanks for the solution. I can understand the actual problem on 32bit. But
> I think still this is a bug.
>
> |
>> | +------+
>> [f]      |
>> |        |
>> [+ 1]    |
>> |        |
>> [% 6]    |
>> |        |
>> [t f f]  |
>> |     +--+
>> |
>
>
> Could you give me the patch again with easily drawing? Sorry I can't
> recognize your patch drawing...
>
> Many thanks,
> akntk
>
> On Mon, Oct 6, 2014 at 1:22 AM, <zmoelnig at iem.at> wrote:
>
>> (had to find a real compuer before anwering the actual question)
>>
>>
>> Quoting Jonghyun Kim <agitato816 at gmail.com>:
>>
>>> Pd 0.45.5 (Vanilla)
>>> Mac OS X Mavericks 10.9.5
>>>
>>>
>>> I don't really know why this bug cause, or only my problem. This bug
>>> sometimes appears. I think this is very critical bug.
>>> [f] storing bug
>>>
>>> [metro 1]
>>> |
>>> [f 0]
>>> |  /
>>> [+ 1]
>>> |
>>> [% 6]
>>>
>>> respected result: 0, 1, 2, 3, 4, 5 (repeat)
>>>
>>> bug: 4, 4, 4, 4, 4 (always 4)
>>>
>>
>>
>> this very much sounds like a problem with floating point precision
>> overrun.
>> an [f] object (and actually *any* number within the Pd universe) will
>> hold a single precision 32bit floating point number, which can only
>> represent *consecutive* integer values up to 16777216.
>> (consecutive means, that [f] can hold representations of both (e.g.)
>> 1000023 and 1000024).
>> if the numbers go higher, singple precision floats will have gaps bigger
>> than 1.0 inbetween them (e.g. the next number after 16777216 representable
>> by [f] is 16777218) - this breaks a counter that increments 1 (since
>> 16777216+1 will be evaulated to ~16777216!)
>>
>> the solution is actually quite simple: never allow your number to grow as
>> big as that.
>>
>> in your counter this means, that the feeback part, must include the [% 6]
>> (so the numbers in the counter will only ever stay in the range 0..6):
>>
>> |
>> | +------+
>> [f]      |
>> |        |
>> [+ 1]    |
>> |        |
>> [% 6]    |
>> |        |
>> [t f f]  |
>> |     +--+
>> |
>>
>> btw, you ASCII rendering of the patch did not use [trigger]. you should
>> always use it when you want to connect multiple inlets to a single outlet.
>>
>> mfgsdr
>> IOhannes
>>
>>
>>
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>
>
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