[r-t] Viking D Royal [was Exhausted search spaces]

Don Morrison dfm at ringing.org
Sun Feb 7 19:21:51 UTC 2010

On Sun, Feb 7, 2010 at 11:42 AM, Mark Davies <mark at snowtiger.net> wrote:
> Educated guess, or did you run a few preparatory searches first?

Some things were relatively straightforward from inspection and hand

- that all the 56s would be easily available so long as I didn't try
  to insert one of the tenor fiddling blocks into the plain course

- that all the 65s would not be readily available if I did insert one
  into the 24365 course, but that I thought that a reasonable trade-off
  for the little bell interest (the limit of 12 65s was just a rough

- that 30 is a reasonable number of 65432s and 23456s to aim for in
  this method in this style of composition

Others became clear only with earlier, exploratory searches

- most notably that 350 was a good threshold for four bell runs front
  and back

That's the sort of stuff I was including in my statement

  "It may also be worth noting that I spent about 65 minutes tinkering
   by hand, and running 18 other searches before settling on this

Thanks for the confirmation that you come up with the same number of
callings as I do. That's always encouraging. This stuff is
sufficiently complicated that I always worry a bit that I'm being too
aggressive and missing some things without knowing it. I'm reasonably
confident that I'll not produce a false composition (and, in any case,
I always prove and format it with a mostly independent bit of
software), but I know I've had some subtle bugs in the past that have
caused me to miss things.

Don Morrison <dfm at ringing.org>
"Enum is actually a generic class defined as Enum<T extends Enum<T>>.
This circular definition is probably the most confounding generic type
definition you are likely to encounter. We're assured by the type
theorists that this is quite valid and significant, and that we should
simply not think about it too much, for which we are grateful."
           -- Ken Arnold and David Holmes, _The Java Programming Language_

More information about the ringing-theory mailing list