<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>They updated libpd to the latest last week.</span></div><div><span>More info to follow.....</span></div><div><span><br></span></div><div><span>;-~</span></div><div> </div><div>Gemnotes-0.1alpha: Live music notation for Pure Data<br>http://sharktracks.co.uk/<br></div> <div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "> <div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "> <div dir="ltr"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Rich E <reakinator@gmail.com><br> <b><span style="font-weight: bold;">To:</span></b> Ed Kelly <morph_2016@yahoo.co.uk> <br><b><span style="font-weight: bold;">Cc:</span></b> PD List <pd-list@iem.at>; pddev <pd-dev@iem.at> <br> <b><span
style="font-weight: bold;">Sent:</span></b> Tuesday, 20 March 2012, 16:37<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PD-dev] Filter design for iPhone<br> </font> </div> <br><div id="yiv1609130415">What do you mean by break, crashes? If yes, what version of libpd are you using? Up until about a month ago, floating point exceptions (such as NAN) would crash libpd, whereas pd-vanilla ignores them. Peter B. recently added a commit that changed this:<div>
<br></div><div><a rel="nofollow" target="_blank" href="https://github.com/libpd/libpd/commit/27c848a56d3d27e62231f8b0d9ef17c7c56cd9f9">https://github.com/libpd/libpd/commit/27c848a56d3d27e62231f8b0d9ef17c7c56cd9f9</a></div><div><br></div><div>Anywho, you'll probably want to take care of those NAN's anyway. :) Not sure why pd vanilla ignores SIGFPE.</div>
<div><br></div><div>cheers,</div><div>Rich<br><div><br><div class="yiv1609130415gmail_quote">On Tue, Mar 20, 2012 at 4:57 PM, Ed Kelly <span dir="ltr"><<a rel="nofollow" ymailto="mailto:morph_2016@yahoo.co.uk" target="_blank" href="mailto:morph_2016@yahoo.co.uk">morph_2016@yahoo.co.uk</a>></span> wrote:<br>
<blockquote class="yiv1609130415gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div><div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "><div><span>Hi,</span></div><div><br><span></span></div>
<div><span>I'm trying to design or find a resonant lowpass filter for use with libPd for Openframeworks running on an iPhone 4.</span></div><div><span><br></span></div><div><span>1. I've tried the rjlib filter attached (filtertest_list.tar.gz) and it works fine in Pd, but instantly breaks when I run it on the iPhone - all other playing audio cuts out, and it is impossible to reset. I suspect that the buffers fb1 fb2 ff1 ff2 ff3 are hitting NAN values and staying there, but I haven't tested this.</span></div>
<div><br><span></span></div><div><span>2. I've had a go at implementing the filter from <a rel="nofollow" target="_blank" href="http://www.musicdsp.org/archive.php?classid=3#25">http://www.musicdsp.org/archive.php?classid=3#25</a> as a Pd external (mvcf~.tar.gz) and it is very
efficient CPU-wise. However, higher values of f or q cause the internal filter buffers to hit NAN and stay there (tested in Pd - I haven't tried this on the iPhone yet).</span></div><div><br><span></span></div><div>
<span>I would ideally like to find out why the second attempt breaks at high q and/or f, as what I want is a 24dB/Octave moog-ish filter. I'm sure those of you with higher math skills will intuitively know why, but I'm just learning calculus now (my early education was a bit chaotic). I'm also limited by the fact that this is for a commercial project (although I'll be happy to share the code :) so I can't just take a GPL external and recompiled libpd with it.<br>
</span></div><div> <br>Ed<br><br></div><div>Gemnotes-0.1alpha: Live music notation for Pure Data<br><a rel="nofollow" target="_blank" href="http://sharktracks.co.uk/">http://sharktracks.co.uk/</a></div></div></div><br>_______________________________________________<br>
Pd-dev mailing list<br>
<a rel="nofollow" ymailto="mailto:Pd-dev@iem.at" target="_blank" href="mailto:Pd-dev@iem.at">Pd-dev@iem.at</a><br>
<a rel="nofollow" target="_blank" href="http://lists.puredata.info/listinfo/pd-dev">http://lists.puredata.info/listinfo/pd-dev</a><br>
<br></blockquote></div><br></div></div>
</div><br><br> </div> </div> </div></body></html>