[next] [prev] [up] Date: Sun, 24 Sep 95 18:35:36 -0400
[next] [prev] [up] From: Jerry Bryan <BRYAN@wvnvm.wvnet.edu >
[next] [prev] [up] Subject: Re: Order problems
On 09/24/95 at 00:31:55 Michiel Boland said:
>Hello all,

Had a great time reading the archives. What I haven't found
there are order problems: what is the shortest (in terms of
quarter turns or half- and quarter turns, whatever you prefer)
transformation of the cube with a given order?

I would be curious to hear how you are doing your search. It is
trivial to see how to calculate the order of a particular
position. However, it is not obvious to me how to find a
position of a particular order. I hope it is not the case that
it is in the archives and I just haven't seen it.

I would guess that you are building a search tree of length 0,
length 1, length 2, etc. as has been done many times before,
and calculating the order of each position as you encounter it.
You could then easily build a table of shortest positions of
each order, provided the order appeared in your search.
I would further guess that you have searched down to about
level 6. However, if that is how you are doing it, I don't
see how you could have proved that the shortest position of
order 110 is of length 8. I don't see how a PC program could
have searched to level 8 in just a little while.

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Robert G. Bryan (Jerry Bryan)                        (304) 293-5192
Associate Director, WVNET                            (304) 293-5540 fax
837 Chestnut Ridge Road                              BRYAN@WVNVM
Morgantown, WV 26505                                 BRYAN@WVNVM.WVNET.EDU

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