parity problems

noobcuber

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Apr 23, 2008
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Hi I have searched all over the net and have only found parity algorimths that switch dedges (double edges). But when I get a single edge or 2 single edges that are not flipped then I am fully stuck.

What would I do in this case?

So for example one would be where the whole top face is orientated but 1 part from 2 different edges is not flipped,, if you can understand this from below. (the slashes representing orientated pieces and the gaps unoriented pieces

/ / / /
/ /
/ / / /
/ / / /
 
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You put the flipped edges together and then use a parity algorithm.

I bet you can do this intuitively if you spend a few minutes on it.

(putting them together, not the parity)
 
well okay then how do you permute a single part of a dedge??

You can't.

I'd say that you have your cube put together wrong but that's actually impossible.

There must be an even number of edges flipped. You can get it down to 2 using a variety of methods, then use a standard parity algorithm.
 
Assuming this is a standard 4x4x4, it's impossible to have just one edge flipped due to the design of the pieces themselves. Each piece has a curve inside the puzzle in order to fit the interior mechanism.


If two of them are flipped, just do as mrbiggs said and 1. put them together, 2. perform parity algorithm, 3. undo setup moves.
 
what do you mean single part?

Do you mean all dedges pair are in correct place but only ONE part of ONE dedge is not?

I don't think this is quite possible....

i agree.

also, can we not say the word dedges? edges led into the word tredges for 5x5x5, but what next? will we have quedges(quadruple edges) on the 6x6x6? say the phrase "I had trouble finding the right quedge" out loud and try not to punch yourself in the face. you can see how this might be a problem, so can we go back to calling them edges and edge pairings like they did in the good old days?
 
what do you mean single part?

Do you mean all dedges pair are in correct place but only ONE part of ONE dedge is not?

I don't think this is quite possible....

i agree.

also, can we not say the word dedges? edges led into the word tredges for 5x5x5, but what next? will we have quedges(quadruple edges) on the 6x6x6? say the phrase "I had trouble finding the right quedge" out loud and try not to punch yourself in the face. you can see how this might be a problem, so can we go back to calling them edges and edge pairings like they did in the good old days?
Okay, could you please tell someone to exchange the right edge of the UF edge with the right edge of the UB edge using a 2-edge switch, then the UL edge and UR edge using the other type of 2-edge switch?

Why not use dedges as long as it's clear, consistent, and -most importantly- convenient? I don't care about quedges and heptedges (hedges? :) ) and spredges and supercalifragilisticedges -I've said sillier things in real life.

Anyhow, to the first post:
I assume you put a space at the beginning of the second row that got incorrectly formatted: b' R' F R b R' F' R
 
what do you mean single part?

Do you mean all dedges pair are in correct place but only ONE part of ONE dedge is not?

I don't think this is quite possible....

i agree.

also, can we not say the word dedges? edges led into the word tredges for 5x5x5, but what next? will we have quedges(quadruple edges) on the 6x6x6? say the phrase "I had trouble finding the right quedge" out loud and try not to punch yourself in the face. you can see how this might be a problem, so can we go back to calling them edges and edge pairings like they did in the good old days?
Okay, could you please tell someone to exchange the right edge of the UF edge with the right edge of the UB edge using a 2-edge switch, then the UL edge and UR edge using the other type of 2-edge switch?

Why not use dedges as long as it's clear, consistent, and -most importantly- convenient? I don't care about quedges and heptedges (hedges? :) ) and spredges and supercalifragilisticedges -I've said sillier things in real life.

Anyhow, to the first post:
I assume you put a space at the beginning of the second row that got incorrectly formatted: b' R' F R b R' F' R

What is the meaning of that?
 
Noobcuber, let us know if you still have a problem. It seems your problem is to flip one single "super edge" (also referred to as "dedge" on 4x4x4). Is that correct? If so, try Chris Hardwick's algorithm:
r2 B2 U2 l U2 r' U2 r U2 F2 r F2 l' B2 r2
which will flip the l and r pieces on a super edge located at the UF position on the cube. (Note "l" is one layer inward from L face and "r" is one layer in from R face. This notation documentation is missing at some sites.)

If you see 2 super edges with flipped pieces, turn them into 3 super edges first, to enable you to turn them into just one super edge with flipped pieces. (To convert 2 dedges to 3, replace a cubie with its mate, for example, Red/Yellow with Yellow/Red cubie.) I don't have a 4x4 handy, but I believe that is what Lucas meant by b' R' F R b R' F' R. You may have intended this diagram:
X X X X
O X X O
X X X X
X X X X
where "O" is used in place of your gaps.
 
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Noobcuber, let us know if you still have a problem. It seems your problem is to flip one single "super edge" (also referred to as "dedge" on 4x4x4). Is that correct? If so, try Chris Hardwick's algorithm:
r2 B2 U2 l U2 r' U2 r U2 F2 r F2 l' B2 r2
which will flip the l and r pieces on a super edge located at the UF position on the cube. (Note "l" is one layer inward from L face and "r" is one layer in from R face. This notation documentation is missing at some sites.)

If you see 2 super edges with flipped pieces, turn them into 3 super edges first, to enable you to turn them into just one super edge with flipped pieces. (To convert 2 dedges to 3, replace a cubie with its mate, for example, Red/Yellow with Yellow/Red cubie.) I don't have a 4x4 handy, but I believe that is what Lucas meant by b' R' F R b R' F' R. You may have intended this diagram:
X X X X
O X X O
X X X X
X X X X
where "O" is used in place of your gaps.

Maybe you meant this one:
X X X X
O X X O
Y X X Y
X X X X

and to convert it to
X X X X
O X X Y
O X X Y
X X X X

Is that what you meant?
 
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