[r-t] Cambridge Major Tenors Together - The Full Monty

Andrew Johnson andrew_johnson at uk.ibm.com
Fri Jun 4 13:37:13 BST 2021

I have created a collection on CompLib
https://complib.org/collection/11125 based on
https://changeringing.co.uk/cambridgefm.htm
I also went through all the compositions on CompLib with the same
characteristics:
Only Cambridge Surprise Major
>= 5000 changes
Tenors together
Tenors strictly together
Standard calls
Normal start

and found 74 compositions. Some of those compositions didn't seem to be
small variations of the 48 representative compositions, so I added all the
compositions to the collection, and categorised the ones over the 48 as
extra or similar. [I think the 48 were just grouped by parts, length and
number of befores].

For similarity I used the following:
Generate the rows for each composition.
When comparing a composition to a reference composition, chose the
rotation / reversal which maximises the number of row + next row pairs in
the composition which match a row + next row pair in the reference.
See
https://lists.ringingworld.co.uk/pipermail/ringing-theory_bellringers.org/2019-February/026966.html

For each composition, try all the other compositions as a reference
composition and find the one with the best match.

That worked reasonably well, and found compositions such as
https://complib.org/composition/35968 which wasn't close to anything in
the Full Monty list.

./c80532.rows=5346 rows c35968.rows=5024 rows rotate 4706:>15643278
start=16542378 same rows=2630 52.35% same next row=2471; 93.95% of same
rows; 49.18% of all rows

As a comparison
https://complib.org/composition/67542
https://complib.org/composition/33105
c67542.rows=5120 rows c33105.rows=5120 rows rotate 3072:>14563278
start=16523478 same rows=5120 100.00% same next row=5112; 99.84% of same
rows; 99.84% of all rows

look similar according to my calculation.

These look very similar:
https://complib.org/composition/10029
https://complib.org/composition/67414
./c10029.rows=5600 rows c67414.rows=5184 rows rotate 0:>12345678
start=12345678 same rows=5184 100.00% same next row=5181; 99.94% of same
rows; 99.94% of all rows

If the conductor was calling #67414, but you thought the conductor was
calling #10029 only 3 times would you be surprised by the next row if you
were just considering the current row.

but it works okay for this situation. Consider just the lead end / lead
head might be better for methods where a different course could be singled
in at one of two places - should every row pair in the singled in course
be counted as a difference or just the calls?

Andrew Johnson
Twyford

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