[PD] list vs. symbol array [was: Re: Licensing issues]
jancsika at yahoo.com
Thu Nov 8 02:45:49 CET 2012
----- Original Message -----
> From: Frank Barknecht <fbar at footils.org>
> To: "pd-list at iem.at" <pd-list at iem.at>
> Sent: Tuesday, November 6, 2012 6:19 AM
> Subject: [PD] list vs. symbol array [was: Re: Licensing issues]
> On Mon, Nov 05, 2012 at 11:38:00AM -0800, Jonathan Wilkes wrote:
>> ----- Original Message -----
>> > From: Frank Barknecht <fbar at footils.org>
>> > On Mon, Nov 05, 2012 at 08:26:17AM -0800, Jonathan Wilkes wrote:
>> >> How many table names total were there in the patch that was
>> >> the device?
>> > I don't remember anymore, that was in 2009, when the abstraction
> was first
>> > posted here on pd-list.
>> > But if you don't believe me, just do some benchmarks on your own
> and compare
>> > array access with list filtering.
>> It makes no difference if the number of table names is around 100. At 1000
>> method is certainly faster-- I've just never had a patch with 1000
> I'm pretty sure, the patch at that time didn't either. The main problem
> was the high frequency with which lookups had to happen. As a special election
> day service I have written a benchmark showing this situation. On my machine
> the symbolarray uses about 16 percent CPU at the "metro" period of
> 0.01 ms
> while list lookup uses 24. Now 0.01 ms may sound like a tempo you won't
> encounter in real music, but that's wrong: In chords you play many notes at
> same time, the "period" then is a very fast 0 ms. This can generate
> CPU usage
> spikes on slow devices if the lookup is too slow - at least that's my
> explanation for why the symbolarray was able to fix the patch.
[symbolarray] does indeed take about half as much cpu as using the message
box. It also takes exactly the same cpu as [makefilename %d-tab] which is
much simpler and doesn't require an abstraction. But maybe you needed
those specific names for the tables for some reason...
A lot of these Pd vanilla prototypes suffer from already being at the very edge
of what can be developed with the prototype. You can't easily add a sort method,
for example, nor can you extend the design to allow each element to be either a
symbol or float without adding two fields to the template struct and a conditional
that would impact the performance gain you get from using an array in the first
place. Not to mention the near-complete lack of operators for symbols which is
why I call it an array of Pet Rocks in this case.
 You can certainly split symbols and count their length in Pd vanilla but it ain't
> Frank Barknecht _ ______footils.org__
> Pd-list at iem.at mailing list
> UNSUBSCRIBE and account-management ->
More information about the Pd-list