Message #4095
From: Marc Ringuette <ringuette@solarmirror.com>
Subject: Re: [MC4D] ClojureScript scrambler and some ideas about a near-optimal solver (plus "Fourtega" variant and my solve video)
Date: Wed, 01 Aug 2018 13:12:17 -0700
Hi Andy! Great stuff. Code, even!
I’m sure a number of us would like to try out your scrambler and any
follow-ons you do. Any chance you’ll either host a web version, or
compile it into a Java jar file, or (ideally) compile it to Javascript
so it can run on anybody’s web browser? (But only if it’s fairly easy
and doesn’t require a complete new set of libraries or something.) We
can easily host a version on one of our websites if it’s just Javascript.
You get style points from me, by the way, for doing an on-the-fly video
solve from a fresh random scramble. Quite a contrast from the previous
one from Jay, who could be heard saying things like "I’ll break up this
block here" as he did his short and sketchy scramble. Just teasing
you, Jay, I like your stuff too. ;)
Your Kociemba-ish numbers seem on target, regarding solution spaces and
how to possibly break up a solution into phases.
Regarding solving code: the first thing I’ve had in mind to try is to
make a definition file for the generic permutation puzzle solver Ksolve
being maintained by Michael Gottlieb. It’s some C++ code that takes a
puzzle definition file and a scramble file as input, and finds solutions
to the scramble.
http://mzrg.com/rubik/ksolve+/
For example, here’s the definition file for a regular 3x3x3.
http://mzrg.com/rubik/ksolve+/3x3x3.def
Although, there’s a subtlety in using this for the 2x2x2x2 because of a
limitation of the code: Michael suggests that a sticker-based version
(where the pieces defined in the file are 64 stickers, not 16 4-color
pieces) would work, but that the obvious version where 16 4-color pieces
are permuted and oriented, would fail due to the assumption that twists
can be added and subtracted commutatively modulo the number of
orientations. Alternatively, I’ve spotted the place in the C++ code
where this assumption could be generalized pretty easily. So, before
anybody tries it, I suggest that you email back and forth a bit with me
to give you a head start. The result of this pretty easy project would
be very useful, but far less than ideal: a piece of executable C++ code
that takes a text file scramble as input and spits out some solutions to
it. It could then perhaps be wrapped in something more palatable, such
as a link to MC4D or to a different interface as below, to become less
painful to use.
Regarding the code I’d most like to see written: a scrambler was on
the list – good job there – but my biggest desire is for a (preferably
Javascript based) virtual physical 2x2x2x2 puzzle. This would open up
the puzzle to more interested people, by a factor of 100 at least! It
would be absolutely huge. Of course, much less tactile and desirable
than a physical puzzle, but far more accessible to all.
The code I envision for a virtual physical 2x2x2x2 would be a lot like
Roofpig from Lars Petrus, which is some nice Javascript code for online
Rubik’s Cube demos.
http://lar5.com/cube/index.html
(click "play" on the cube animation on the right to see it in action; a
link to the Roofpig code is at the top right of the page).
However, glancing at the code, I see that Roofpig is very 3x3x3
dependent. It would be a total rewrite, but perhaps a helpful place to
start.
Another piece of code that would be cool to see: a hugely simplified
MC4D version, not a port at all, and once again preferably in
Javascript, to solve only the n^4 hypercubes. It wouldn’t use the 4D
projection code at all, but instead would show 3D cubical stickers
flying around in a 3D workspace, analogous to how my sticker-based demo
can be performed in real life. Since such a program would be 10x
simpler than MC4D and would run in any browser, it could open up the n^4
hypercube puzzles to more people also.
Then, of course, we wire all three of these projects together with
side-by-side automated physical and virtual 2^4 solvers, and … this is
getting out of hand. ;)
Cheers
Marc