<p dir="ltr">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:</p>
<p dir="ltr">(-1*base)^exp*e^(pi*exp*i)<br>
Which is (-1*base)^exp*cos(pi*exp)<br>
when base is a negative number </p>
<p dir="ltr">this assumes the standard branch cut in complex analysis:<br>
-1=e^(pi*i) and not e^(3*pi*i) or any other</p>
<p dir="ltr">Chuck<br></p>
<div class="gmail_quote">On Apr 23, 2013 9:11 PM, "Ivica Ico Bukvic" <<a href="mailto:ico@vt.edu">ico@vt.edu</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
It may be a bit more complex since exponent values between -1 and 1 are the<br>
ones that generate imaginary numbers from negative values, with the<br>
exception of 0 which generates 1. Latest pd-l2ork patch tries to fix this.<br>
See:<br>
<br>
<a href="https://github.com/pd-l2ork/pd/commit/95d82d33d2580a00e32d725e0f5147d88cdaf3" target="_blank">https://github.com/pd-l2ork/pd/commit/95d82d33d2580a00e32d725e0f5147d88cdaf3</a><br>
70<br>
<br>
> -----Original Message-----<br>
> From: <a href="mailto:pd-list-bounces@iem.at">pd-list-bounces@iem.at</a> [mailto:<a href="mailto:pd-list-bounces@iem.at">pd-list-bounces@iem.at</a>] On Behalf Of<br>
> IOhannes m zmoelnig<br>
> Sent: Tuesday, April 23, 2013 6:21 AM<br>
> To: <a href="mailto:pd-list@iem.at">pd-list@iem.at</a><br>
> Subject: Re: [PD] Negative input numbers for [pow] return 0<br>
><br>
> -----BEGIN PGP SIGNED MESSAGE-----<br>
> Hash: SHA1<br>
><br>
> On 2013-04-23 11:50, Joe White wrote:<br>
> > Out of curiosity, are the workarounds suggested more of a result of<br>
> > the difficulty of extending the Pd core rather than the<br>
> > implications that such a change might have?<br>
><br>
> the implementation would be trivial (merely removing the safeguards<br>
> that currently clamp the value to 0)<br>
><br>
> fgmasdr<br>
> IOhannes<br>
><br>
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> 0<br>
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