5 ms·

But is it actually "solving" itself? Or just recording the scramble and playing it back in reverse order? I realize it's an artificial distinction, but if the c

• aidos 8y ago
  Looks like it's solving to me. It's taking longer to solve and there's a screenshot of some solving code in the description. I notice also that it appears to not be able to move the middles sections, so instead it twists the middle and one side and then twists the side back again - so that adds an extra inefficiency. EDIT if you look at the first video, the first move the solver makes is not the inverse of the last one the player made, so I'm sure it has its own solver. Also, there are pretty standard solver algorithms (I've never looked them up because I don't want to spoil the game for myself but I have a really inefficient one I've figured out myself).
  • bunderbunder 8y ago
    I'm pretty sure it's using some version of Fridrich. It looks like it in the video, and the source code screenshot has a file name, "solve_f2l.cpp", that would appear to be referring to the "first two layers" step, which is usually abbreviated as f2l. For finding a solution by computer, it has the advantage of being almost completely a rote application of algorithms.
• nearmuse 8y ago
  It is not as relevant, it is the hardware that looks cool.
• zeptomu 8y ago
  That does not really matter I think. The cool part is that they very able to build a cube that looks similar like Rubik's but has electronics and motors embedded that are able to turn it. Solving the cube with a computer is a solved problem for a long time and there are myriads of algorithms. Granted the solutions are not perfect (i.e. using the minimum number of steps needed which is always <= 20), but mostly come close (~25 steps).
  • benmowa 8y ago
    note too a replay solution could have infinite steps to have to reproduce, assuming its not optimized to take any shortcuts to jump to a re-occurring state.
  • adrianmonk 8y ago
    I think it has psychological significance. It's one thing to have an object that violates expectations by taking action that an outwardly similar object does not. It's a surprise move that turns the tables on the person interacting with the object. (You could almost view it as a threat or a power dynamic thing.) Having those actions be as intelligent as possible raises this surprise to another level. If I fiddled with it for 5 minutes and it put it back in 30 seconds, I'd feel even more like I just got owned by the object.
• SAI_Peregrinus 8y ago
  Given the source code screenshot it looks like it's using CFOP to solve, so it's not just replaying a scramble.
• montenegrohugo 8y ago
  You can see its not just playing back the reverse order: - first human shuffle move was rotate around white side - last cube movement was rotation around green side Ergo the cube did not just follow the same steps in reverse order
  • deleted 8y ago
    [deleted]
• Aardwolf 8y ago
  I don't think one is much harder than the other (since solver algorithms already are a solved problem), the hardware seems more impressive to me than whether you put software on it that tracks and reverses movement or has a solver algorithm in it. From the video it looks like a solver algorithm by the way, and not going for least amount of movements either, it seems to move much more during the solve than the movements the person did. To save battery they should go for optimal amount of moves!
• izzydata 8y ago
  A Rubiks cube solving algorithm seems like a trivial part of the problem if you can run code on it and give commands to make various turns already.
• modernerd 8y ago
  It's solving itself. The C++ snippet includes permutations for the Fridrich method's first two layers (F2L), which wouldn't be required for a reverse-replay.
  • zyngaro 8y ago
    It does need to know it's starting configuration though ! So it starts from a solved cube and needs to record the steps to compute the starting unsolved configuration.
    • deleted 8y ago
      [deleted]
• stormbrew 8y ago
  A lot of people have pointed out that solving a cube isn't really a Hard Problem, and that the really interesting thing is the automechanic aspects of it to begin with, but honestly I think it'd actually be harder to make it track the rotations and replay them backwards than to just solve the cube from any static state. Kinda feel like this is a pretty good example of how solutions to problems can be counterintuitive to people.
  • canadaduane 8y ago
    Doesn't it need to track the rotations in order to solve it anyway though?
    • enriquto 8y ago
      Why? It just needs to record the current position, regardless how it got there.
      • justbaker 8y ago
        That's how I solve a partially solved cube when I pick them up -- just look at where it is and what's next, don't worry about how it got there.
        • jawnv6 8y ago
          It doesn't have eyes. Or, perhaps more significantly, a way to track the edge and corner cubelets from the initial "solved" position to the current configuration. Face angle isn't enough, you need the path that was taken to get there.
          • justbaker 8y ago
            Gotcha, so in other words, it needs the previous spin to help decide what’s next? (It doesn’t have self-perspective)
      • unholiness 8y ago
• csa 8y ago
  It was mixed 10 times (half rotations counting as 1). It was “solved” with 56 moves. Seems like a solve algo to me.
• johnhenry 8y ago
  The problem here is that "self solving" would necessitate that the cube be able to determine what is "wrong" with itself and ultimately figure out not only the "right" self-configuration, but how to get there. That may be a bit much to ask of a cube considering how hard it is for a human to do that. Stranger still, it might turn out that the cube decides that it's fine the way it already is and it doesn't need to conform to a "right" configuration based on our expectations. In which case; perhaps we're already invented what you're looking for?
  • krankthat 8y ago
    Yeah -- what I'm most curious about is how it determines its initial state. Does it need to be powered up and "zeroed" like a scale before it's scrambled? How does the algorithm know which actuator needs to be moved and which direction it needs to be moved in?
• PDoyle 8y ago
  No, to me it looks like it did CFOP with an orange cross on the table, and the white cross when he held it in his hand.