[PD] Negative input numbers for [pow] return 0

[Charles Z Henry]

Yep.  It's damaging to have NaN's propagating around in Pd. [pow] having a
single output means that you only want real values.  The result is not a
real number-I think the result should just be set to 0 (perhaps 1 depending
on what the worst usage case is).  Would it be better to have pow just
output the real part of the complex number, generated from:

(-1*base)^exp*e^(pi*exp*i)
Which is (-1*base)^exp*cos(pi*exp)
when base is a negative number

this assumes the standard branch cut in complex analysis:
-1=e^(pi*i) and not e^(3*pi*i) or any other

Chuck
On Apr 23, 2013 9:11 PM, "Ivica Ico Bukvic" <ico at vt.edu> wrote:

> It may be a bit more complex since exponent values between -1 and 1 are the
> ones that generate imaginary numbers from negative values, with the
> exception of 0 which generates 1. Latest pd-l2ork patch tries to fix this.
> See:
>
>
> https://github.com/pd-l2ork/pd/commit/95d82d33d2580a00e32d725e0f5147d88cdaf3
> 70
>
> > -----Original Message-----
> > From: pd-list-bounces at iem.at [mailto:pd-list-bounces at iem.at] On Behalf
> Of
> > IOhannes m zmoelnig
> > Sent: Tuesday, April 23, 2013 6:21 AM
> > To: pd-list at iem.at
> > Subject: Re: [PD] Negative input numbers for [pow] return 0
> >
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > On 2013-04-23 11:50, Joe White wrote:
> > > Out of curiosity, are the workarounds suggested more of a result of
> > > the difficulty of extending the Pd core rather than the
> > > implications that such a change might have?
> >
> > the implementation would be trivial (merely removing the safeguards
> > that currently clamp the value to 0)
> >
> > fgmasdr
> > IOhannes
> >
> > -----BEGIN PGP SIGNATURE-----
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> > iEYEARECAAYFAlF2YIEACgkQkX2Xpv6ydvQyoQCgiC95SRoOKaOHu6qkmpX+kD8
> > 0
> > /ugAoJymAbmtt6qWkZM5rAlObyhdarRF
> > =KUIu
> > -----END PGP SIGNATURE-----
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