So the only way is to delete the seed and restart the sketch? Short answer; "no". Long answer; a PRNG (pseudo random number generator) typically consists of a number and a function. The function is set loose on

Hey, Lars, Let me address your points in reverse order; the number and the outcome becomes the new number and is returned as the random value. Sometimes only part of the number, like the least significant bits are returned. It follows that these functions must make sure this series of numbers takes a long time before they repeat, that the "seed" simply determines at what part of the cycle we start and that talking about "deleting the seed" doesn't actually make a lot of sense.

That's very sad! A seed is perfect to get a repeating pattern, but sometimes it's nice to turn off the seed to get non repeatable values.

I'm not sure whether this is "sad"... it's simply a fact of life in computer science. The numbers are never really random and *if you knew the seed* they are easy to repeat. They just look random and for a decent PRNG it should be very hard to figure out what the seed was. This might be so hard that we'd all be gone by the time some process determines it.

So; in practice this difference between repeatable numbers and truly random ones shouldn't matter too much. On the other side; it may very well be that something went wrong in the case of ChucK? Yours, Kas.

On 11 September 2010 15:31, Lars Ullrich wrote:

Hi Kas,

Hey, Lars!

I was looking for a message to turn off the seed. Something like "set seed to 0" and get non repeatable structures. (like maxmsp object lp.tata from peter castine )

The default situation should be getting a initial seed from the host OS when the VM starts. That seed should be unknown to you, but it's still a seed. There really is no way to "turn off the seed" with PRNG's. Sorry; it's not my fault ;¬).

Anyway, I have found a method to do this with some functions.

Thanks a lot for your patience.

No problem, that's what the list is for,

Yours, Kas.

Hi Stefan, I like to use a seed in many tasks, specialy for sequencing. Maybe this example helps you to understand what I mean: Std.srand(1200); //set your seed int SeedArray[8]; //fill your array with random numbers fun void CalcRndArray() { for(int i; i < SeedArray.cap(); i++) { Std.rand2( 1 , 1000 )=>SeedArray[i]; } } CalcRndArray(); while (1) { for(int i; i < SeedArray.cap(); i++) { <<>>; } <<<"--------------", "we always get the same numbers" >>>; 2::second=>now; } // image reading your arrays randomly, but with a repeating structure. // if you want another structure, just change the seed. in that case the seed will be your pattern // and if you don't want a structure, leave the seed or change it with a function. Hope this helps! Lars Am 11.09.2010 um 15:46 schrieb Stefan Blixt:

This thread has made me thoroughly confused. I see that you have solved your issue, Lars, but I would still like to know what your task was. :) I feel it might be good for inspiration.

In my world of computer science, if you use a random generator, pretend that you've never heard the word "seed", and just start reading random numbers, you will effectively get non repeatable structures, different every time.

/Stefan

2010/9/11 Kassen

On 11 September 2010 15:31, Lars Ullrich wrote: Hi Kas,

Hey, Lars!

I was looking for a message to turn off the seed. Something like "set seed to 0" and get non repeatable structures. (like maxmsp object lp.tata from peter castine )

The default situation should be getting a initial seed from the host OS when the VM starts. That seed should be unknown to you, but it's still a seed. There really is no way to "turn off the seed" with PRNG's. Sorry; it's not my fault ;¬).

Anyway, I have found a method to do this with some functions.

Thanks a lot for your patience.

No problem, that's what the list is for,

Yours, Kas.

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Gotcha! Or at least, I can see a flaw here in ChucK's randomizers: there is only one of them! My immediate reaction to seeing your code was that it ought to be simplified to this: while (1) { Std.srand(1200); //set your seed for(0 => int i; i < 8; i++) { <<>>; } <<<"--------------", "we always get the same numbers" >>>; 2::second=>now; } But this won't work if you use the randomizer elsewhere in your code. if someone calls Std.rand2() before the loop above has finished, the random sequence will be corrupted. It will work here though, since there is no wait statement inside the for loop, but I suspect Lars's code is more complicated than this. Other programming languages will usually have some kind of randomizer object (e.g. "Random" in Java or the result of the seed function in PovRAY), that you instantiate with a seed (if you want) and then use independent from other random instances. If we had that you could write this code: 0 => int resetSeed; Std.makeRandomizer() => Random r; while (1) { if (resetSeed) { r.srand(1200); //set your seed } for(0 => int i; i < 8; i++) { <<>>; } <<<"--------------", "we always get the same numbers" >>>; 2::second=>now; } ...without clashing with other usage of randomizers (I made up some function and class names). Was it something like this that you ran into, Lars? /Stefan 2010/9/11 Kassen

Hey, Lars!

I'm not Stephan, but I'm still a bit confused as well so I thought I'd answer anyway.

Std.srand(1200); //set your seed

...

Looks fine

<<<"--------------", "we always get the same numbers" >>>;

...

That's what we'd expect, yes.

...

Hope this helps!

Well.... no, not really.

What happens if you don't set the seed with srand(), do you still get the same numbers? As I understand things now you should get exactly what you are looking for by simply not setting the seed in line 1. Could you verify that by not setting the seed at all you get different numbers each time you run your program? If not we have a bug. I seem to remember there was a issue like that on Windows, which might be caused by Windows (last time I looked) not having the "storage" of OS-event based random numbers that Unix typically uses; that might be the cause. That's no excuse though; as we are not trying to secure nuclear missiles (I hope!) something like the time in ms should yield a perfectly serviceable seed at VM startup.

Yours, Kas.

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Let me add to the confusion (but it's really not so complicated): A: If you want "random" behavior: do nothing. The random number generator is seeded with the time of day. B: If you want repeatable random numbers (i.e., you want to get the same sequence of numbers each time you run the program), then call srand() with the number of your choosing. ... and shoot me if I've gotten that wrong. I haven't loaded ChucK onto my new laptop to verify this.

On 11 Sep 2010, at 22:37, Stefan Blixt wrote:

Sorry if I'm just acting like my head is made of wood, but 1: why would anyone want to reproduce a chuck program sample-accurately?

One application is if one is experimenting with different parameters in combination with randomizers to produce different kinds of sounds, and then want to select a cool combination. With THX Deep Note they did not do so, resulting only having the recording. http://musicthing.blogspot.com/2005/05/tiny-music-makers-pt-3-thx-sound.html

What happens if you don't set the seed with srand(), do you still get the same numbers?

No.

Could you verify that by not setting the seed at all you get different numbers each time you run your program?

I get different numbers. I think there is no bug, everything works like expected.. (for me) By the way, I've noticed that Std.srand dont like double integers..

Was it something like this that you ran into, Lars?

mmm.. sorry Stefan, but I'm not sure what you mean? I was looking for a way to put off the seed and get to the normal "random mode". Now I'm using a function Std.rand2(1,1000)=>int NewSeed and then I jump back to my stored seed, like in your code. Lars Am 11.09.2010 um 18:21 schrieb Stefan Blixt:

Gotcha! Or at least, I can see a flaw here in ChucK's randomizers: there is only one of them! My immediate reaction to seeing your code was that it ought to be simplified to this:

while (1) { Std.srand(1200); //set your seed for(0 => int i; i < 8; i++) { <<>>; } <<<"--------------", "we always get the same numbers" >>>; 2::second=>now;

}

But this won't work if you use the randomizer elsewhere in your code. if someone calls Std.rand2() before the loop above has finished, the random sequence will be corrupted. It will work here though, since there is no wait statement inside the for loop, but I suspect Lars's code is more complicated than this.

Other programming languages will usually have some kind of randomizer object (e.g. "Random" in Java or the result of the seed function in PovRAY), that you instantiate with a seed (if you want) and then use independent from other random instances. If we had that you could write this code:

0 => int resetSeed; Std.makeRandomizer() => Random r; while (1) { if (resetSeed) { r.srand(1200); //set your seed } for(0 => int i; i < 8; i++) { <<>>; } <<<"--------------", "we always get the same numbers" >>>; 2::second=>now;

}

...without clashing with other usage of randomizers (I made up some function and class names).

Was it something like this that you ran into, Lars?

/Stefan 2010/9/11 Kassen Hey, Lars!

I'm not Stephan, but I'm still a bit confused as well so I thought I'd answer anyway.

Std.srand(1200); //set your seed

Looks fine

<<<"--------------", "we always get the same numbers" >>>;

That's what we'd expect, yes.

Hope this helps!

Well.... no, not really.

What happens if you don't set the seed with srand(), do you still get the same numbers? As I understand things now you should get exactly what you are looking for by simply not setting the seed in line 1. Could you verify that by not setting the seed at all you get different numbers each time you run your program? If not we have a bug. I seem to remember there was a issue like that on Windows, which might be caused by Windows (last time I looked) not having the "storage" of OS-event based random numbers that Unix typically uses; that might be the cause. That's no excuse though; as we are not trying to secure nuclear missiles (I hope!) something like the time in ms should yield a perfectly serviceable seed at VM startup.

Yours, Kas.

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And you can still accomplish what you'd like to do, I hope?

yes! everything is fine. thanks

Could you be a bit more specific?

sorry, I meant Std.rand. can you run this code please: while(1) { <<>>; 2::second=>now; } Lars Am 11.09.2010 um 19:51 schrieb Kassen:

I get different numbers. I think there is no bug, everything works like expected.. (for me)

Great! And you can still accomplish what you'd like to do, I hope? Crisis averted?

By the way, I've noticed that Std.srand dont like double integers..

Could you be a bit more specific? This sounds like there might be a real issue after all.

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