[PD-dev] [PD] Filter design for iPhone

[Mathieu Bouchard]

Le 2012-03-22 à 00:39:00, Ed Kelly a écrit :

> I'm anxious to know what limit is reached in the coefficients of the 
> filter that causes the undefined result (NaN).

I haven't seen the code, but I just want to make you notice that adding 
together -Infinity and +Infinity results in a NaN ; so does subtracting 
two infinities of the same sign.

So, the NaN might happen when two expressions that are supposed to 
partially cancel each other, happen to both overflow, in different 
directions.

There are various possible causes for NaN, but with formulas that only 
involve +, - and *, the possibilities are a lot more limited.

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| Mathieu BOUCHARD ----- téléphone : +1.514.383.3801 ----- Montréal, QC