Big Cubes' Parity

[mrCage]

Hi

The shortest pure edge swap i found on 4x4x4 so far is like so:

1: l' U2 l 'U2 F2 l' F2 r U2 r' U2 l2 (swap with center side effect)
2: U l' r' u2 r l U' l' r' u2 r l (corrects centers)

Combined (2 + 1 NOT 1 + 2) =
U l' r' u2 r l U' l' r' u2 r U2 l 'U2 F2 l' F2 r U2 r' U2 l2 (22 - stm)

I'm sure better can be found, but it's not trivial.
A pure edge swap looking like a dedge flip (the normal OLL parity) seems even more tricky. I will find one if time allows !!

- Per

 

[mrCage]

Hi

I was able to cut it down to 21 turns like so

1 = U2 l.F2 l' F2 r F2 r' F2 U2 r'
2 = [l' r' U l r,u2] = l' r' U l r u2 l' r' U' l r u2

Now insert 2 into 1 at the dot and we get

U2 r' U l r u2 l' r' U' l r u2 F2 l' F2 r F2 r' F2 U2 r'

Small improvement, and not nicer to perform

-Per

 

[Mike Hughey]

Thanks, Per - that's really nice to see how you came up with those. I hadn't thought of using a fewest-move-type approach to try to come up with these sorts of algorithms.