Hello everybody,

I've made a post regarding random seed in the past, but I found that recently, it seems that the way random seed works in Pd has changed. For context, I've had a generative MIDI patch for a couple of months now, and each time I open it, I'm able to consistently get the exact same tone arrangement each time.

I don't know what happened, but when I open the exact same patch, I now get a totally different array of tones, and I'm not quite sure what happened. The patch is the same – but something changed and the tones are no longer the same. I know this is a vague issue to have without something more concrete, but I'm generally wondering whether anything did change in recent versions of Pure Data.

Does anybody know what might be going on?

BTW [random] gets seeded this way:

static int makeseed(void)
{
    static unsigned int random_nextseed = 1489853723;
    random_nextseed = random_nextseed * 435898247 + 938284287;
    return (random_nextseed & 0x7fffffff);
}

So every [random] instance gets a new seed.

If you deleted and recreated a [random] object (this would happen if you edited [random 20] to [random 30] for instance), then upon the next load, it would be created later than it had been previously, acquiring a different seed and producing a different sequence. (And... explicitly seeding would override that.) It should be easy to reproduce that.

hjh

Still, the behavior of a patch is supposed to be consistent across different pd versions

1. Create a patch like this (creating the lefthand [random] first):
2. Save it as patch-A.pd.
3. Edit the lefthand [random] to be [random 101].
4. Then edit it back to [random 100] (note, do not ctrl-z undo here).
5. Save this as patch-B.pd.

23-0316-random-seq-A.pd
23-0316-random-seq-B.pd

Now, if you quit Pd, open patch-A, and click it at the top:

R: 92
R: 66
R: 10
R: 73
R: 38
L: 74
L: 56
L: 76
L: 48
L: 55

And quit, relaunch, load patch-B, and:

R: 74
R: 56
R: 76
R: 48
R: 55
L: 92
L: 66
L: 10
L: 73
L: 38

... whereupon L and R have switched value sequences.

Sure, these aren't the same patch, but the difference is invisible to the user, who would assume that they are the same and then assume that "something changed in Pd."

Still, the behavior of a patch is supposed to be consistent across different pd versions

No disagreement there, but the OP didn't actually say that a Pd version upgrade caused the problem. I'm starting to doubt that it's a Pd version thing.

hjh

@ddw_music I added a [bang] + [$0] + [number] to my patch just to check the order of abstraction creation, and saved it. Now it is consistent across Pd versions...... but with the new [random] sequence 2nd 3rd 4th (see my post above).
Conclusion..... something something nothing.
If I posted the original.... I probably did...... then I will check in a text editor this evening.
Certainly the patch window opens with different window coordinates in later versions..... a lot of whitespace at the top...... so "something" changed.
David.
P.S. Its a mess in a text editor.... window coordinates for every object have changed and the object ordering is all over the place..... to the point that I don't think I will be able to analyse the changes.....
So this evening I will start the patches and resave them in previous versions of wish..... maybe that is where the conundrum will be solved.

wish has nothing to do w/ patches getting saved in pd.. pd does that part on its own afaik

Hi everybody – so sorry for the multiple month delay. I got sidetracked in life and totally lost track of time.

Something I didn't previously note is that this issue is the same across the board with all of my other generative MIDI patches. The configuration of pitches changed for all of them. I thought it was this specific project, but that does not seem to be the case whatsoever. I'm beginning to wonder whether this is a computer-specific issue. I have the MacBook with the M1 chip. Could that be at play?

Also, I have tried to go back in Pd versions, and that did not fix anything.

My conclusion is twofold:

1. Next time, purposefully set up a random seed (how do I do that by the way?) so that my patch can be reproducible.

2. Embrace the randomness. My patch is meant to be generative MIDI music, so technically, I'm being anal retentive in trying to preserve this particular configuration. The whole point is that it's supposed to be random, I just fell in love with a certain configuration, which is ironic.

Thank you all for your help. All the help you've offered is beyond the scope of my knowledge, so I appreciate you all having a go at it.

the helpfile for random shows how to send a seed message to the left input of [random}

@caska This is helpful, thank you. Is there any way to seed the entire patch? I use a lot of random objects, so I'm guessing would have to seed every single one in the patch.

@Maks so, im thinking you could do send and receive objects for the seed values maybe...
I have yet to fool around with seed much... or rather... yet to have any use of random that seems to be much affected by it.