Randomised Sequences that Stick

Creations & Ideas
1

Inspired by @martin’s code (thank you) here’s my go at a randomised sequence generator, where the sequence stays stuck until I want to change it. I’m sure this will be useful.

But this is the point where someone gently points out that Sam’s written an in-built one already.

I’m starting to want to have my own function library - is that possible?

#Sequencer Generator
#Randomised sequences that stick
use_bpm 80

define :getseq do |length, notes, seed|
  #Generate a randomised sequence based on the seed
  seq=[]
  use_random_seed seed
  for i in 0..length-1
    seq.push(notes[rrand_i(0,notes.length-1)])
  end
  seq.ring
end

notes = scale :C4, :major, num_octaves: 1

#Change the sequence length and seed
seq1 = getseq(7,notes,1)

live_loop :main do
  8.times do
    play seq1.tick, amp: 0.2
    sleep 0.25
  end
end

live_loop :bass, sync: :main do
  play :C3, amp: 0.2
  sleep 1
end
3 Likes
2

You can define individual functions, and then allow them to be available on Sonic Pi start up using init.rb - is that close enough?

1 Like
3

Yes that’s ideal, thanks

1 Like
4

In fact I think that something like this is just a useful - slightly different effect but easier to code live! A randomised sequence that repeats - that’s the key thing. My ideal would be a sequences that gradually evolves rather than hops between states.

use_random_seed 5
    seq = notes.shuffle
    in_thread do
      16.times do
        osc "/midi4x4",seq.tick,127,0.1,1,1
        sleep 0.25
      end
end
1 Like
5

Re function library, I do a similar thing by defining my utility functions in a dedicated file, and then using run_file in init.rb :+1:

1 Like
6

That sounds good, I’ll experiment

7

NB if you use the latest 3.3beta on Mac released to Patreon supporters today then be aware that the location of init.rb has moved to ~/.sonic-pi/config/init.rb from ~/.sonic-pi/init.rb

1 Like
8

Windows and Raspberry Pi me.

The ring operations take, shuffle etc. are rich pickings for this directed randomness. But I’ve decided what I need is a shuffle that where I can control the amount of shuffling if you see what I mean. I think I should be able to do that. Like you specify how many elements get swapped, or how far apart they are.

9

I built my own prototype version of exactly that too a little while ago. Haven’t used it for a little while, so I forget if it was fully tested and working :joy: but I was also wanting such a thing. I am hopeful that a version of it will make its way into the official functions.

1 Like
10

Ah ah, great minds :smile: I think this would be really good for the live stuff I’m working on now, so I’ll give it a go too.

EDIT mind you, the existing ring functions are at least as rich as what you get in a modular sequencer and more flexible in combo, so maybe I should exhaust those possibilities before chomping at the bit for new functions. Users…can’t live with them…

2 Likes
11

I have found the new use_random_stream command in latest SP3.3.0beta useful for controlling what is selected. I itilised it for example in my beethoven mashup program I haven’t published this yet because it contained this command, which I used in my own build. I changed the selection during the program using use_random_stream [:white,:pink].choose to change the effect of subsequent “random” commands.

1 Like
12

Oh yes, that does look interesting. With a bit of experimenting now I have found some nice ways of using the ring functions to give more of evolving feel to a sequence. I guess at bottom I’m trying to hear some of the conventional ways to cadance a solo - increasing complexity, embellishment, motivic development. Simply adding more randomness (which is the easiest to do) is a way, but a bit of a one-trick pony. I think this new use_random_stream could help things along.