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rubik clockwise turn

asked 6 years ago

mchericoni gravatar image

updated 6 years ago

The 2D map of the Rubik’s cube after the F move shows the F face rotated anticlockwise. Shouldn't it be a clockwise turn?

sage: rubik = CubeGroup()
sage: print(rubik.repr2d("F"))

                 +--------------+
                 |  1    2    3 |
                 |  4   top   5 |
                 | 25   28   30 |
    +------------+--------------+-------------+------------+
    |  9  10   8 | 19   21   24 | 43   26  27 | 33  34  35 |
    | 12 left  7 | 18  front 23 | 42 right 29 | 36 rear 37 |
    | 14  15   6 | 17   20   22 | 41   31  32 | 38  39  40 |
    +------------+--------------+-------------+------------+
                 | 11   13   16 |
                 | 44 bottom 45 |
                 | 46   47   48 |
                 +--------------+
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The question is easier to study if you provide a complete set of commands that allow others to reproduce your problem from a fresh Sage session.

Please edit your question to provide that.

slelievre gravatar imageslelievre ( 6 years ago )

I edited the question and added the commands to reproduce the issue.

mchericoni gravatar imagemchericoni ( 6 years ago )

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answered 2 years ago

The encoding of the moves seems to me indeed inconsistent.

If you apply the following move:

C = RubiksCube().move("U*R")    
C.solve()
'U*R'

The calculated solution by the internal solver 'U*R' is actually the solution for the inverse sequence 'R^-1 * U^-1'.

If I plot the Cube C it gives:

             +--------------+
             | 38   36   33 |
             |  2   top   7 |
             |  1    4    6 |
+------------+--------------+-------------+------------+
| 48  34  35 |  9   10   11 | 17   18   3 | 27  29  32 |
| 12 left 13 | 20  front  5 | 26 right 31 | 45 rear 37 |
| 14  15  16 | 22   23    8 | 25   28  30 | 43  39  40 |
+------------+--------------+-------------+------------+
             | 41   42   19 |
             | 44 bottom 21 |
             | 46   47   24 |
             +--------------+

That's the output one would expect for the sequence 'R^-1 * U^-1', not the sequence 'U*R' applied to the cube.

But if I use the C.show() command, it's displayed in the correct way. The same for the 3D option with C.show3D(). (Sorry, can't add the pictures, not allowed to upload something.)

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answered 6 years ago

nbruin gravatar image

All the moves are encoded as counterclockwise by the looks of it. However, if you are imagining that the cube in unfolded in such a way that you're looking at the inside of the cube, you can interpret the moves as clockwise.

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Asked: 6 years ago

Seen: 867 times

Last updated: Nov 20 '18