Re: [chuck-users] Non-random random number

Thanks for letting us know about this. After some investigation, it looks like a bug in the underlying C functions rand()/srand(), which are widely regarded to be pretty bad like this. Each of those STK ugens re-seeds rand() with the current time in seconds, via srand(), when the ugen is created. Evidently the first value out of rand() after this reseeding is not very random at all, and would explain what is happening here. ChucK could probably do a better job working around those limitations, but new code should definitely use Math.random() and related functions. spencer On Wed, Oct 9, 2013 at 4:37 PM, David Loberg Code wrote:

'Noise' object does not interfere. 'SubNoise' does.

david

All of those instruments contain noise. Likely a Noise object. Wonder if Noise itself does a seed? I'll check.

Sent from my iPhone

On Oct 9, 2013, at 4:40 PM, David Code wrote:

Apparently, the non-random bug does not happen after declaration of all STK instruments, just some of them: BlowBotl, BlowHole, Clarinet, Flute, Saxofony, StifKarp, VoicForm

And the problem occurs with both Std.rand2 and Std.rand2f (I haven't conducted any more tests yet to see under what other conditions it might happen.)

david

Forgive me if this was already discussed on the list before. I am puzzled about a non-random random number. When the random number is calculated right after an STK instrument is declared, the result is not random. It is the same number every time. However, if the same code occurs without an STK declaration before it, the result is random.

while (true) { StifKarp stu => dac; int randy; Std.rand2(0,10) => randy; <<<"here are three random numbers", Std.rand2(0,10), Std.rand2(0,10),Std.rand2(0,10), "and NON-random Randy", randy >>>;

Std.rand2(0,10) => randy; <<<"here are three more random numbers", Std.rand2(0,10), Std.rand2(0,10),Std.rand2(0,10), "and random Randy", randy >>>; 1000::ms => now; }

david

David Loberg Code School of Music Western Michigan University 1903 W Michigan Ave Kalamazoo, MI 49008-5434code at wmich.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

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*From: *David Code *Subject: **Re: [chuck-users] Non-random random number* *Date: *October 9, 2013 6:37:13 PM EDT *To: *chuck-users@lists.cs.princeton.edu *Reply-To: *ChucK Users Mailing List

Upon a quick check it appears that Math.random is fine. I guess I just need to retro-fit my older ChucK files.

david

Does it do it with Math.random too?

-Jeff

-- Jeffrey Albert, Ph.D. Assistant Professor of Music Industry Technology Loyola University New Orleans College of Music and Fine Arts 6363 St. Charles Ave. Campus Box 8 New Orleans, LA 70118

Office: Communications/Music Complex 428P Office Phone: (504) 865-2606 Voice & Text: (504) 315-5167jvalbert at loyno.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-usershttp://www.loyno.edu/~jvalbert

On Oct 9, 2013, at 4:40 PM, David Code https://lists.cs.princeton.edu/mailman/listinfo/chuck-users> wrote:

...

* Apparently, the non-random bug does not happen after declaration of all STK instruments, just some of them:*>* BlowBotl, BlowHole, Clarinet, Flute, Saxofony, StifKarp, VoicForm*>* *>* And the problem occurs with both Std.rand2 and Std.rand2f*>* (I haven't conducted any more tests yet to see under what other conditions it might happen.)*>* *>* *>* david*>* *

On Oct 9, 2013, at 5:40 PM, David Code wrote:

Apparently, the non-random bug does not happen after declaration of all STK instruments, just some of them: BlowBotl, BlowHole, Clarinet, Flute, Saxofony, StifKarp, VoicForm

And the problem occurs with both Std.rand2 and Std.rand2f (I haven't conducted any more tests yet to see under what other conditions it might happen.)

david

Forgive me if this was already discussed on the list before. I am puzzled about a non-random random number. When the random number is calculated right after an STK instrument is declared, the result is not random. It is the same number every time. However, if the same code occurs without an STK declaration before it, the result is random.

while (true) { StifKarp stu => dac; int randy; Std.rand2(0,10) => randy; <<<"here are three random numbers", Std.rand2(0,10), Std.rand2(0,10),Std.rand2(0,10), "and NON-random Randy", randy >>>;

Std.rand2(0,10) => randy; <<<"here are three more random numbers", Std.rand2(0,10), Std.rand2(0,10),Std.rand2(0,10), "and random Randy", randy >>>; 1000::ms => now; }

david

David Loberg Code School of Music Western Michigan University 1903 W Michigan Ave Kalamazoo, MI 49008-5434code at wmich.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

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