August 2008 - chuck-users - lists.cs.princeton.edu

Chuck Concurrency Best Practices
by mike clemow 02 Sep '08

02 Sep '08

Hi everyone, So, I've been struggling to find a method to leverage the concurrency model in Chuck and I keep running up against the same issue: my guts tell me to do things that I can't do because of fact that child processes are alive only as long as the parent and the fact that objects are only passed by reference. Let me unpack this for you. I'm building a granular synthesis class library for Chuck. Most everything is being cast as one of two types of objects: 1) Forkable - a process that takes parameters and can be run or sporked 2) Forker - an object that knows how run a process and will fork it out for you. In order to get over the fact that functions are not (yet) datatypes in Chuck which can be passed to other functions, I'm basically following the example that Kassen, Mike, et al. were discussing in this forum topic: http://electro-music.com/forum/viewtopic.php?highlight=functor&t=23546 My problems always seem to rise from the fact that every Forker (whose job it is to fork a process) also has to be aware of how long that process is going to take or else run the risk of dying before it's child has completed. This leads to infinite passing of responsibility for time and every Forker seems to also need to be a Forkable and have it's own Forker, et cetera ad inifinitum. At higher and higher levels of abstraction, finding the duration of a process BEFORE it runs and figuring out how to handle it, is requiring more and more analysis and feels... for lack of a better word, "wrong" to me. This is compounded by the fact that the objects I'm passing into these functions (methods of other objects) can only be passed by reference and it's increasingly difficult to set-and-forget these processes, since they constantly reference other global objects. The passing by reference is fine, but I find myself wishing I had the choice to make a copy. Now, it's entirely probable that I just haven't caught on yet and am going about this process in a completely backward way. Does anyone here run into similar issues and (even better) have good methods of avoiding them? One idea I have considered is to make a Forker a looping process that receives Events as input, rather than an object with methods. As this would require a(nother) complete re-write, I'm stalling. ;-) So, how do you manage your concurrent processes in Chuck? Cheers, Michael PS: Love dynamic Arrays! Can't wait for those SC/Smalltalk-like array methods! -- http://semiotech.org/wp-prod/ http://semiotech.org/michael

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I: taps+chuck+osc
by Giacomo 28 Aug '08

28 Aug '08

Da: Giacomo [mailto:giacomo.serafini@poste.it] Inviato: giovedì 28 agosto 2008 17.58 A: chuck-users(a)lists.cs.princeton.edu Oggetto: taps+chuck+osc Hi, Im a computer sciences student at Udine (Italy) university. Im working on a thesis about tapestrea, in my opinion really a great tool. Recently Ive experimenting with chuck; Ive found great documentation on tapss and chucks official sites, but Im interested in a very specific subject: is there a way to synthetize a sound in taps (running on localhost) and reproduce this sound in another host (in the same wired network)? Ive already looked at chuck osc examples, they work great, but I would use a sound synthetized by tapestrea. Thanks for your help (and sorry for my English) Giacomo

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Neural Nets in ChucK
by Inventor-66＠comcast.net 26 Aug '08

26 Aug '08

Hi, Did I read correctly that ChucK now has support for neural nets? I've been coding neural nets in the signal path and in the time loop, and my beloved ChucK is so slow that I can only do 30 neurons or so in real time. I would like to hear more about this new feature. I looked on the Unit Generators page and didn't see anything there. What's up? Les Hall (Inventor) http://www.freedomodds.com/music/ <--- my ChucK web page : )

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newbie questions
by joachim heintz 25 Aug '08

25 Aug '08

Hi - I'm new in ChucK (up to now I used mainly Max and Csound). I like the language and would like to use it for my next piece, which will be for trombone and live-electronics. What I need is: 1. record the live input (6 microphones) in buffers and play the content back later (in parts); 2. live transposition via fft (like the gizmo object in Max); 3. working on partials (e.g. changing the amplitudes or selecting any). I think this is not very sophisticated, but after having a look in the documentation and the examples I don't know whether it can be done in ChucK, and how. So I'd appreciate a lot if anyone can tell me where I can find some examples. Thanks in advance! joachim

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Filter.coefs (STRING )
by Kassen 23 Aug '08

23 Aug '08

Dear list, I'm helping a friend with a project and would like to use ChucK to analyse some signals. In particular I'd like to calculate the average of a audio signal over the last n samples (where n is something between say 500 and 1000). The best strategy I can come up with right now is to use Filter and give it a series of n coefficients that make it add the current input sample, the last...... the one n-1 samples ago, all at a amplitude of 1/n, and not use any feedback. This would make Filter do all the work which is good because typically Perry and Gary write C that's much, much faster then the ChucK I write. The bad news is that the docs make it clear that Filter takes a input of type string but it doesn't tell us how this string is formatted. I'm fine generating the string I need procedurally but I would need some more instructions then that it's a string and a rough idea of what's in it. I'd also like to suggest the doc's would be updated with this because as they are Filter isn't that practical to use. Yours, Kas.

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read/write text from file
by Joel Matthys 21 Aug '08

21 Aug '08

Does ChucK a method of writing and reading ints, floats or strings from a file? The documentation only includes WvIn and WvOut for file I/O. I hacked a technique for sending data by scaling it to values -1.0 to 1.0 and sending it to a sound file: //WRITE1.ck// // write values to file Step x => WvOut file => blackhole; "data" => file.sndFilename; float n; for (int ii; ii<20; ii++) { ii/20.0 => n; <<< n >>>; n => x.next; 1::samp => now; } file.closeFile(); These values can then be read sequentially with WvIn: //READ1.ck// WvIn w => blackhole; "data.snd" => w.path; float n; repeat(20) { 1::samp => now; w.last() => n; <<< n >>>; } But I don't get exactly the same values returned; ie, I try to store the value 0.500000 but when read, I get 0.500015. That's a significant variance. Does anyone know where this variance comes from, or how to get around it? And is this the only way to store and read data? What about strings from files? Joel

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chuck arguments
by N. Cameron Britt 16 Aug '08

16 Aug '08

Renato, If you know the sizes of your vectors you could simply pass the elements of your vectors as separate arguments and populate the various arrays in chuck. The following makes two arrays -- one with two elements, one with three: chuck test.ck:1:2:3:4:5 test.ck as follows: int vect1[2]; int vect2[3]; for( 0 => int i; i < me.args(); i++) { //fill vect1 if(i == 0) { for( 0 => int i; i < vect1.cap(); i++) { Std.atoi(me.arg(i)) => vect1[i]; } } //fill vect2 if(i == 2) { for( 0 => int i; i < vect2.cap(); i++) { Std.atoi(me.arg(i+2)) => vect2[i]; } } } for(0 => int i; i < vect1.cap(); i++) { <<<"vect1", vect1[i]>>>; } for(0 => int i; i < vect2.cap(); i++) { <<<"vect2", vect2[i]>>>; } test.ck outputs: vect1 1 vect1 2 vect2 3 vect2 4 vect2 5

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chuck arguments
by Renato Fabbri 15 Aug '08

15 Aug '08

Hi Chuckists, chuck -s test:walk-sample:silence-rest:loop:ap-ppa-appp:3-1-2_1-2-3-4-5-7-6 test.ck is as follows: <<<me.args()>>>; for(0=>int i; i < me.args(); i++){ <<<i, me.arg(i)>>>; } and outputs: 5 :(int) 0 walk-sample 1 silence-rest 2 loop 3 01-001-1000 4 3-1-2_1-2-3-4-5-7-6 i undestand that ChucK has only atof and atoi to get values from incomming strings. and i but 01-001-1000 is/are three vectors: [0,1], [0,0,1] and [1,0,0,0]. and 3-1-2_1-2-3-4-5-7-6 is/are actually two vectors: [3,1,2] and [1,2,3,4,5,7,6]. the first arguments are stringed options passed to ChucK scripts, seems okay. i need these two separate ordered sets of vectors.. i am thinking of sending each value independently (test:.....:4:6:9......) separating each vector by, say, 999. and each set of vectors by 9999 any better idea?

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Asio build (please?)
by Kassen 12 Aug '08

12 Aug '08

Fellow ChucKists, Would there perhaps be somebody who has some experience with building on Windows and who could spare the time to roll me and others like me a ASIO version of the latest& greatest? Perhaps somebody already has? I'd like to use the latest version but I'd also like the have decent latency on Windows, judging by the download stats on the forum (where the previous versions were hosted) there is a significant amount of interest in this; the last version (by Moudi) was downloaded 34 times, the version before that (by Philippe) 184 times, I'm not sure exactly how many ChucKists there are but I suspect those to be signifficant numbers. Eternal gratitude as well as a drink if/when/where we meet shall be yours. Cheers, Kas.

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.size() fails to properly instantiate objects
by Kassen 10 Aug '08

10 Aug '08

Fellow ChucKists, Below you'll find some example code proving that extending a array of instances of a home-made class using ".size()"doesn't properly instantiates the new objects, leading to nullpointers and the shred being dropped. The "<<" operator, using "new" does lead to proper instantiation. I feel this is a bug. Yours, Kas. =====================8<============================== //instantiate a array of home made classes foo bar[1]; //check that this works <<<"your lucky number is ", bar[0].value>>>; //grow by one. bar << new foo ; //make sure it's instantiated <<<"your lucky number is ", bar[1].value>>>; //grow by a another one bar.size(bar.size() + 1); //make sure we did, size should now be 3 <<<"size is now", bar.size()>>>; //try to verify this is instantiated, it won't be <<<"your unlucky number is ", bar[2].value>>>; class foo { Std.rand2(0, 10) => int value; } ===================================================

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