Upload
amber-campbell
View
235
Download
0
Tags:
Embed Size (px)
Citation preview
Say ‘No’ to Random
Last year I presented a paper about a simple system for music (arpeggio) generation
Remarked most arpeggio programs give a few simple algorithms plus a random one
Showed you could derive more complex results with simple system and no random number generator
I subtitled it Say ‘no’ to Random
Say ‘no’ to Yellow?
Matthew Lewis of ACCAD at Ohio State remarked,
“Kevin, when you say, Say ‘no’ to random to some its like you’re saying, Say ‘no’ to yellow
Which is to say, randomness is a valid and essential part of the creative process.
Why Does Kevin Hate Random Number Generators? I don’t so much hate them… As I find them overused, or misused
A (very) brief history of Chance in Music 18th and early 19th century Musikalisches
Würfelspiel (musical dice game) The mid-1900’s saw the establishment of aleatoric (or
‘chance’) music, defined as “music in which some element of the composition is left to chance or some primary element of a composed work's realization is left to the determination of its performer(s)” [2].
Merce Cunningham’s use of dice throwing just prior to a performance to determine the order of the choreography, costumes, lighting, décor, and music
John Cage used very sophisticated techniques beyond that of simply throwing dice
Brian Eno’s Oblique Strategies
Uses of Randomness
Produce surprise Remove some decision making Add complexity, variety
Chance can be used to further the creative process New insights, new solutions can appear
Approaches to Complexity
What do we mean by complexity and randomness? One sometimes ends up discussing the apparent
complexity of an artifact But then to understand this better we need to
understand: Perception
How our senses encode could affect what complexities we more or less easily perceive
Cognition Cultural context, learning, etc.
Lots of Challenges
Extremely important subjects! But not easy to understand Faced with contradictions
Things that look complex (e.g. fractals) can be quite easy to generate
The Complexity Reader ™
ComplexityReader
Notions of Complexity and Randomness It became clear that different disciplines have
different notions of complexity and randomness Architecture, industrial design, visual arts, craft, music,
computer science I thought it would very helpful if we as a community
could share these definitions and hopefully come to a more complete understanding
I thought I would start! The Computer Science perspective…
But do we really need randomness?
Produce surprise Not required if the generative process is sufficiently rich
Remove some decision making One ‘decides’ at a higher level, accept the details
Add complexity, variety Not required if the generative process is sufficiently rich
Example of Information Content
Want to transmit to you the string, “123123123123123123123123123123”
Seems long! “Hmmm but that’s just “123” repeated 10x! Or is it “123123” repeated 5x? “123123123123123” repeated 2x? Which is more right?
Algorithmic Complexity
Kolmogorov Complexity defines the complexity of a string as being the smallest Turing machine (think program) capable of producing the string
So “123” repeated 10x is the shortest way to express it That’s its information content Because it’s the easiest way of getting it back Note: only of theoretical interest
Its a Generative Approach!
It doesn’t matter if it looks complex Only if it was complicated to make it (lets pause and consider that for a moment)
What it Means to be Random
Random numbers are numbers where the shortest Turing machine for producing them is, in fact, the number itself
There’s no discernable structure, no shorter way of encoding it
Random Number Generators Aren’t Random Random number generators aren’t random (termed
pseudo random) They simply produce a sequence of numbers which
are well distributed probabilistically Run it again with same seed, you get same sequence All are relatively simple functions Thus their computational complexity is low Random number generators produce simple results
Random Number Generators Considered Harmful As a designer, an artist, I want to make use of
everything I know: my aesthetic sense, my cultural learnings, my formal training, intuition…
Thus I need to control the system to some degree to express that and approach my goals
With randomness, how do you get the result you wanted? Pick from N results (manual, fitness functions, etc) Reduces predictability But that predictability is required for us to navigate the
space of possibilities You become a shopper © Celestino Soddu 2006
Stuck on Structure
I’m all about the structure, process Given this grammar, what’s the space of expression? What’s in, what’s out? How do the rules combine to produce variety?
Inherent beauty and marvel of the intricacies of the system
It’s a legitimate and fun endeavour to explore these systems
But random number generators get in the way of that Guidance becomes more complex (e.g. goal functions) Can’t tell if the complexity is coming from the generative
system or the randomness
Big on Expressiveness
How do we ensure that the generative systems remain expressive?
How do we ensure that the artist/designer can encode humanity in the result?
Can we use the process like one uses a musical instrument? Takes time to get good at Explore the space of what you can express with it
Complexity without Randomness
Simple L-System
S=F
F=F[-F]F[+F]F
Add rules to make ambiguous
S=F
F=F[+F]F[-F]F
F=F[+F] F
F=F[-F] F
Random Results
What if just Picked Each in Turn?
S=F
F1=F[+F]F[-F]F
F2=F[+F] F
F3=F[-F] F
{1, 2, 3, 1, 2, 3, …}
Longer Sequences
S=F
F1=F[+F]F[-F]F
F2=F[+F] F
F3=F[-F] F
{3, 3, 2, 2, 1, 1, 2, 2, 3, 3}
Your telephone number mod 3…
Splat (2000)
Macroscopic Control with Free Microscopic Variety
Bug Art – Steven R. Kutcher
Observations
You can get results that look random by adding just a small amount of information
That’s because the generative process is quite rich A random number generator is overkill Plus it interferes with our ability to explore how the
rules interact to produce variety What if result was close but not quite what you
wanted? They obscure the inherent beautiful complexity of the
system We mistakenly attribute the complexity to the random
number generator
Conclusions
It is difficult to discuss complexity because we have many definitions
Two approaches to complexity:1. What it looks like (experiential) – this is complicated
because must understand perception, cognition, etc.2. How it was made (algorithmic) – this is complicated by
the fact that difficult or impossible to analyze It would be beneficial if we could come to a better
shared understanding and terminology It would be fantastic if someone from the visual arts
could present that world’s notions of complexity, someone from cognitive science, …
Conclusions (2)
Use of randomness is a valuable tool in the creative process
But simple systems are able to produce complex, surprising results without the need for random number generators
This allows us to more directly explore the system Understand how rules combine so can drive the
process, achieve intended results There are an infinite number of computable functions
in the world. When you’re looking to explore a generative system, don’t always reach for the random number generator, try a different one!