[r-t] Cyclic 7-parts of major

[Don Morrison]

On Wed, Sep 25, 2019 at 4:57 PM Andrew Johnson <andrew_johnson at uk.ibm.com>
wrote:
> Just noodling around using plain bob lead-ends for a part-end gives
> higher CompLib scores than true cyclic scores, but I don't know if
> this is by chance as there are some high scoring cyclic compositions
> on CompLib.

I suspect it’s probably a result of at least two factors:

• While I find it rather difficult to get my head wrapped around the
composite “music” score complib quotes, it does appear to include CRUs,
both at the back and the front of rows, internal runs, and to give an extra
kick to 56 flavored rollups. It seems reasonable to suppose the first and
third of those three might lead to a bit of an advantage for Plain Bob lead
things.

• But even if not, it is surprising how closely aligned, under various
constraints, the maximum numbers of runs (of 4 bells, front and back only;
don’t know if it applies to longer ones or internal ones) for the two
different styles of seven parts seem to be. I don’t really grasp why this
should be, but empirically it seems to. Perhaps it has something to do with
the distribution of such runs between parts, and between leads more or less
removed from the part heads? I’ve no evidence to back up such a conjectured
explanation, though. I’m guessing someone brighter than I will tell us
within twenty-four hours!

I naïve assume that odd ball part heads, still of order 7, probably won’t
do as well as the more natural Plain Bob and cyclic ones, but I wonder if
that assumption is actually warranted?


-- 
Don Morrison <dfm at ringing.org>
“I’ll grant you it’s obvious. Trouble is, just because
things are obvious doesn’t mean they’re true.”
                        — Terry Pratchett, /Wyrd Sisters/
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