[r-t] Method classification question
Andrew Johnson
andrew_johnson at uk.ibm.com
Fri Jun 2 12:34:43 UTC 2017
> From: Ben
> >Andrew Johnson wrote:
> >34.45,4
> >Lead-end 3124685079
> >6 leads, 24 change round block
>
> >>From a construction point of view:
> >Front 3 bells plain hunt
> >4 is fixed
> >Back 6 treble bob
>
> I don't understand this. How do the front 3 bells plain hunt? Surely
> both 45 and 4 in the place notation imply both 145 and 14
> respectively, which cause nothing like a plain hunt? To my mind,
> there are two leads at every (even) stage and the back bells do not
> treble bob either.
>
> Ben Newsam_______________________________________________
The comma in the place notation is significant
34.45,4
expands to
34.45.34.4
See http://www.ringing.org/methods/
"More generally the comma operator is an unfolding operation for notating
palindromes: the changes before the comma, save the last, are repeated in
reverse order; and similarly those after the comma, the results of the two
unfolding operations being concatenated. The place notation may contain at
most one comma."
There are some other conventions:
http://www.boojum.org.uk/ringing/Ringing-PlaceNotation.html
"Compound place notation is a series of pieces of place notation separated
by commas. Each piece may start with an ampersand (&), in which case it
represents a symmetrical sequence of changes: for example, the two strings
&-2-3-4,5 and -2-3-4-3-2-5 are equivalent."
http://www.ringbell.co.uk/methods/umd.htm#pn
"In a method where the place notation is symmetrical around the half way
point only half of the lead and the lead end is recorded. So Shipway Place
3.145.5.1.5 le 125 may be expanded to 3.145.5.1.5.1.5.145.3 le 125 As it
is symmetrical about last '5'. To expand it you omit the last term and
work backwards through the notation and add the lead end. Methods
symmetrical in this way are known as 'Palindromic'."
http://www.abelsim.co.uk/doc/placentn.htm
"If you prefer, you can show the reflecting portion using the ‘&'
character, and separate out the lead end place notation using the ‘+'
character:
&x1x1x1+2
Abel also accepts Central Council method groups, which allows you to
specify Plain Bob Minor as:
a &x1x1x1
"
http://www.ropley.com/eril-instructions.aspx
"Reversal statements:
Many (most) methods and principles have place notation symmetry about the
middle of a block of changes. A shorthand way of representing a block that
is the reverse of another block of place notation is to use the reversal
operator '~. Note this is not the same as the reversal operator of the
MicroSiril method libraries, where the last place (at the half lead) is
not repeated in the reversal, and the whole expansion includes the forward
as well as the reversed sequence or places. Eril just provides the
reversal of another block via the reversal operator. Example:
HalfLeadOfKent = 34-34.16-12-16-12-;
LeadOfKent = HalfLeadOfKent + 16 + ~HalfLeadOfKent + 16;
"
Andrew Johnson
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