[PD] bug in wrap~?

[Orm Finnendahl]

Hi IOhannes,

 thanks, your explanation helped finding a way to solve this for my
specific problem.

--
Orm
----------------------------------------------------------------------
Prof. Orm Finnendahl
Komposition
Hochschule für Musik und Darstellende Kunst
Eschersheimer Landstr. 29-39
60322 Frankfurt am Main

Am Donnerstag, den 07. März 2019 um 11:15:54 Uhr (+0100) schrieb IOhannes m zmoelnig:
> On 07.03.19 10:53, Orm Finnendahl wrote:
> > Hi,
> > 
> >  today I encountered something which seems to be a bug in wrap~
> > (pd-0.49.0) on my architecture.
> 
> probably not a bug in [wrap~].
> 
> > The attached patch shows that wrap~
> > ist outputting a 1 instead of the expected 0 when inputting the
> > division of 880 by 220. Inputting the value 4 with sig~ to wrap~
> > doesn't cause this, so I assume the result of the division is
> > represented differently internally.
> 
> yes.
> 
> just connect:
> 
> |
> [< 1]
> |
> [print]
> 
> to see that what you perceive as "1" is really a wee bit smaller.
> 
> 
> after that, try getting the error by replacing the above with:
> 
> |
> [* 262144]
> |
> [- 262144]
> |
> 
> any big number would do, but 262144 is a power of two (2^18), so it
> keeps additional errors (introduced by the scaling) low.
> 
> the scale/subtraction gives an error of "-0.0625" (it should be "0", if
> "1" really was "1"), which is -1/16.
> 
> unscaling gives an (absolute) error of 2^-22, which is about to be
> expected when dealing with numbers in the 128-1024 range.
> 
> fgm,asdr
> IOhannes
> 




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