[PD] abs~ and exp~ fixes [was: rjdj]

Frank Barknecht fbar at footils.org
Sun Mar 29 16:44:19 CEST 2009


Hallo Volker,

ah, there's a bug in d_math.c

Actually there are two: on is reported as "exp~ broken/fixed - ID: 2638371",
but the same issue affects abs, too. Patch for both is attached. 

(I hadn't recognized this because it seems I was using a different [abs~].
Freakying object aliassing...)

Ciao
-- 
Frank

volker b?hm hat gesagt: // volker b?hm wrote:

> for some reason my mails to the list take ages until they arrive, which 
> makes a discussion a little difficult...
>
> ok, something weird going on here. abs~ is not doing what i would think 
> it should be doing - calculating the absolute value of the incoming 
> signal. instead it simply seems to pass input to output (no errors in pd 
> window).
>


>
> if i replace abs~ with an abstraction then it works and the zipping is 
> gone.
> this happens here with pd vanilla 0.42-4.
>
> just tried pd-extended and there it works with abs~.
>
> what could be wrong with my vanilla abs~?
>
>
>
>
> On 29 Mar 2009, at 14:54, Frank Barknecht wrote:
>> Hallo,
>> volker b?hm hat gesagt: // volker b?hm wrote:
>>
>>> thanks for posting this.
>>> for certain freqs i hear a noticeable periodic "zipping" in the sound
>>> (try 230 hz e.g.).
>>
>> Hm, I don't hear it, but that may be my ears.
>>
>>> since the algorithm is based on the sinc function (sin(x)/x), i  
>>> wonder
>>> how pd handles divide by zero in the signal domain. wouldn't you  
>>> have to
>>> check for that in the code/patch?
>>
>> A [/~] with no signal in the right inlet in Pd gives 0 as output.
>> In saw~.pd x never becomes zero, it's always at least 1.8955. :)
>>
>> Ciao
>> -- 
>> Frank
>>
>> _______________________________________________
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>

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