[r-t] parity

[Mark Davies]

> Here's my problem, although admittedly I may be missing
> something very obvious. I don't do it this way.
> Say you have the row 16732845.

Come on Michael, that's a row. To convert to a CO of course you need to know
where it appears in the touch you're ringing; basically, whether at a -ve
or -ve treble position in the method. Usually you do know this...

The system still works on rows though, as I said, and is much quicker than
John David's method, although you may need to use that to start with to
clear out extra bells:

6732845
8673245     get rid of 8th, count 4, +ve
8763245     get rid of 7th, count 1, -ve

That didn't take long, and we can stop there, because 63245 is
self-evidently a negative CO, hence overall we are positive. Job done. You
could do the same by converting to a course end if that makes you happier:

6732845
6732458     get rid of 8th, count 2, +ve
6324578     get rid of 7th, count 4, +ve

Leaving 63245 again, -ve CO hence +ve course end, hence +ve.

Basically you don't have to keep counting for every bell - you stop when
there's only 5 left and use the lookup. All clear now?

MBD