[r-t] Are FCH's needed any more?

King, Peter R peter.king at imperial.ac.uk
Sat May 22 13:16:37 UTC 2010

```I'd be inclined to agree with Graham on this. Although, pushing the analogy further, it is still important to understand how the log function works and how it can turn products into sums (and antilogs - ie exponential- does the opposite). Understanding what these functions do and mean is always going to be important (similarly for FCHs) but we wouldn't use these functions in the same way these days.

What I would be far more interested in learning about is how we can use these concepts in computer proof and composition generation. There's lots of discussion in this list about SMC32(and similar) and trees and nodes etc it would be very informative to have an explanation of these and a simple training example of how to use these to generate compositions more efficiently. Could someone do that?
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From: ringing-theory-bounces at bellringers.net [ringing-theory-bounces at bellringers.net] On Behalf Of Graham John [graham at changeringing.co.uk]
Sent: Saturday, May 22, 2010 12:49 AM
To: ringing-theory at bellringers.net
Subject: [r-t] Are FCH's needed any more?

When I was at school, we had to learn how to use log tables to multiply and divide. Then, along came calculators, and the log tables became redundant.

FCHs were a marvellous invention to simplify the job of proving compositions and find an existing composition that worked for a new method, but the question arises  of how much value they have today when a computer can generate and check all the individual rows in a composition in a fraction of a second? Technology has increased our expectations of compositions from achieving an original objective of just being true, to getting the absolute maximum of music from a method. FCHs were a compromise, in that, for simplicity’s sake, you only worried about the falseness of whole courses. Yes, this then developed into looking at the incidence of the groups to individual leads, but this was a refinement which added further complication (and risk of error) back into the process.

Manual techniques are often not the most appropriate when developing algorithms for programs. For example, SMC used false leadheads and  pre-calculated the false lead pointers for every lead that could be reached given the calling constraints. SMC32 optimised this further by using false nodes (falseness between calling positions). Another option is to use truth tables rather than falseness tables. The fact is that, like calculators and log tables, computers take away the need for FCH tables as a tool.

So should someone new to composing like Alex be worrying about what FCHs are, or should he take a completely new approach? I think you can probably argue this both ways. Yes, it is useful to understand past methods and build upon them*, but it is also good to utilise the knowledge and technology of the day to take the next leap forward, bringing completely fresh ideas and techniques.  Composers tend to be people who like solving problems, and most of those I have met say that they were self-taught. Perhaps this is a requirement for the role, if you are not just going to repeat what others have done before.

Graham

*And therefore I do think it would be good to have FCHs explained on the wiki.

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