Hi,
I have just realized this, and thought it would be helpful to know for
anyone playing with Sage's Rubik's cube abilitites. Here it is:
While the following 3 commands:
sage: CubeGroup().move("U")
and
sage: CubeGroup().plot3d_cube("U")
and
sage: RubiksCube().move("U").show3d()
all take the convention that U means "move the face U clockwise",
unfortunately the command
sage: RubiksCube().move("U")
assumes that U means "move the face U counter-clockwise".
So yes, doing foo= RubiksCube().move("U") and printing foo displays
something that is not consistent with what you get when calling
foo.show3d().
I thought it was something to do with 3d plotting being left-handed in Sage
or whatever, but no, foo.show() also gives the "right" answer. And the
convention for what the permutation U is, taken by CubeGroup and given in
Joyner's book, is just not the one appearing when you print foo.
It seems that inverses are taken, since RubiksCube().move("R*U") displays
something that corresponds to U^-1 * R^-1 (by which I mean U^-1 first, then
R^-1).
In a nutshell: the __str__ method in RubiksCube seems to be broken, somehow.
This is all quite confusing !
best
Pierre
--
You received this message because you are subscribed to the Google Groups
"sage-support" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-support.
For more options, visit https://groups.google.com/d/optout.
