Re: algorithms for dance

David Rodger (
Sat, 18 Apr 1998 10:53:51 +1000

Nick Rothwell wrote:
> - the
>distinction between algorithmic music and interactive music is rather

To which Richard Povall replied:
>Nick, I can't agree with you on this one.

I think I know what Nick means, but I'm sure he'll jump in if I'm
misinterpreting him...

Let's assume one uses a single algorithm to determine the pitch of the next
note played. The input to the algorithm could be (1) a pre-existing
collection of data; (2) real-time input from a transducer, perhaps attached
to a body, or (3) the result of the previous iteration through the

>I work with both approaches to
>building music/sound worlds, and, while I might use algorithms in the
>making of interactive work, I think the end result is typically completely
>different. For me, the purpose of making interactive environments is that
>their outcome (whether that be sonic or visual) is rooted in the body and,
>in my current work, in the live act of speaking.

Seems to me that the algorithm and the machine performing it don't know
anything about the source of the data on which they operate. Their
business is not even "knowing"; they just do what they do. The fact that
(2) could involve a body is significant to the performer but not the
process. So, while the result might be "proportional" to, or determined in
some way by, the nature of the movement, and so seems interactive, the
process (passing of a datum through an algorithm) is the same.

Richard Grevers wrote:
>hmm, I hadn't realised that an infinite series by definition is not an
>algorithm. (And my dictionary confirms the finite bit). Computers calculate
>many values by summing infinite series and stopping when they reach the
>limit of their precision.

Perhaps the notion of an infinite process comes from the practice of
feeding results back into the algorithm. As logn as this is allowed to
happen, the algoirthm keeps on producing results and it can seem like an
infinite process rather than an infinite repetition of a finite process.

Richard (Povall), perhaps you could explain. Is the difference only
because your bodyu is involved? Or is the "machine" process fundamentally
different in either case?

Regards, David

David Rodger ------------ Audio Engineer, Pool Lifeguard, RLSS Trainer
Personal: (not yet exciting)
Research: (a bit more exciting)
"Officially the La Trobe Music Department is in existance for the next
2 years and will close on 31 December, 1999. (This is really just our
way of avoiding the Y2K bug)." -- David Hirst