Message #485

From: David Smith <djs314djs314@yahoo.com>
Subject: Re: [MC4D] Introduction to the 4D_Cubing Group
Date: Wed, 30 Apr 2008 23:11:22 -0000

Hi Roice,

Thank you very much for pointing me to that website! I had
not seen that website before. As for my program, it is not
going well; I have very limited coding experience. For one
thing, the program works but the data it generates is
incorrect. It is overly complicated. It is currently specific to the
4^4 cube. And when I run it and generate the data, it takes GAP over 5
hours to process the data! In short, I need to find a way
to either write a program that tests whether a specific
position is possible, for a 4D (preferably, N-D) cube of any size,
or do the same with an existing program. I have tried to analyze
the code for Don’s N-dimensional Rubik’s Cube solver, but
it is beyond me.

I would be extremely grateful if you or any others in
this group could help me understand the algorithms involved
when testing whether a position is possible for higher-dimensional
cubes. The reason I can’t simply use Don’s program is that
I need to study larger cubes of 4 (preferably any) dimensions.
I definitely need to study 4^4, and perhaps 5^4, I am not
sure yet. And eventually I hope to tackle cubes of more
than four dimensions. As I said, I tried to understand Don’s
code for 2^k and 3^k cubes, but could not understand it.

The only functionality of my program that I need is
the ability to test whether a position is solvable. Any
help you provide, no matter how little, would be greatly
appreciated. I hope I’m not asking for too much. If
there is anything I could do to reciprocate your kindness,
please let me know. Of course if I find the answers I am
looking for, this group would be the first to know!

Once again, thank you for all of your help. I will let
you know if I make any more progress.

Best Regards,

David

PS: I just recently realized that you helped write the code for the
5-dimensional Rubiks Cube program. Amazing!

— In 4D_Cubing@yahoogroups.com, "Roice Nelson" <roice3@…> wrote:
>
> Hi David,
>
> The computer program sounds like a cool project :) After reading
this last
> post, I thought I would also point you to Don’s solving code page
just in
> case you hadn’t seen it.
>
> http://www.plunk.org/~hatch/MagicCubeNdSolve/
>
> His solver is actually hooked up to the MC4D UI under "Edit->Solve
(For
> Real)" (we’ve wanted to do the same for MC5D, but haven’t). The
reason I
> mention it in the context of your email is that I’ve used it to
> answer similar questions to the example you gave. By manually
editing the
> log files, then seeing if the resulting position is solvable, one
can test
> whether certain states are reachable in the 4D cube (I recently
looked at
> possible types of checkerboards). So again, just mentioning in
case it
> could help you with your current goals, but it sounds like you are
already
> well on your way since you are already taking down software bugs.
>
> Btw, I have some 3^3 puzzles with the pictures on them, though I
didn’t know
> they were called supercubes, and I hadn’t heard of super-supercubes
before.
> That’s a pretty neat extension!
>
> cya,
>
> Roice