[WR] Megaminx 59.33 Single Takumi Yoshida

Hmm, I never thought about that. It's true, the vast majority of megaminx states can't be reached by the current scrambler. There are I think about 2^226 states, so we reach at most 1 in 2^156. Question is whether that's bad.
 
I agree with Mike
Laetitia got a lucky solve, not a lucky scramble...

specially on megaminx, your solve is influenced a lot byt the moves you do when making the cross. You can either pair up something by accident or "un-pair" it...
 
Of course we can have lucky solves on megaminx !
Like Arnaud said, sometimes, lots of pairs are already connected, etc.
Sometimes you can get a good time with magical pairs already done, and sometimes with magical look ahead.

Actually, on this video, we can't see if it's a lucky solve or not^^
 
only 2^70???
think about that number please

Arnaud, it's smaller than you think. 2^70 = 1.18 x 10^21... and there are 4.3 x 10^19 possible 3x3 positions. And for comparison, our old "25 random 3x3 moves" scrambler had 3.03 x 10^29 possible scrambles! So 2^70 really is a very small number for such a big complex puzzle.

You are thinking mathematically. I am thinking realistically. 2^70 is such a huge amount that noone will ever encounter a studied situation or even a scramble that he has already solved. Even when you are color-neutral chances of just a "star-skip" are "0".

The big question is if there is an (important) difference between the positions that can be reached and the positions that can't be reached.

I thought there had been a discussion about always performing R++/R--, R+/R- or allowing R+/R++/R--/R- where the final conclusion was that using only R++/R-- gave better scrambles.
 
You are thinking mathematically. I am thinking realistically. 2^70 is such a huge amount that noone will ever encounter a studied situation or even a scramble that he has already solved. Even when you are color-neutral chances of just a "star-skip" are "0".

That's not important because it never happens on other puzzles either. Have you ever seen a random 3x3 scramble and said "I've seen this scramble before"? But even if you haven't seen the scramble before or have a solved case, you can still get very easy solves. On 25-move 3x3 scrambles I've seen several cases with a solved 2x2x2 block or a 3-move xcross or something silly like that; maybe the chance is "0" to you but I've seen it, it CAN happen. And if you have much fewer possible scrambles than there should be, it's very possible that you are excluding more of the 'harder' scrambles, so you might have a higher chance of a lucky or easy case than you normally would.

The big question is if there is an (important) difference between the positions that can be reached and the positions that can't be reached.
Yes, this is an interesting question, but one that might not be able to be answered...
 
You are thinking mathematically. I am thinking realistically. 2^70 is such a huge amount that noone will ever encounter a studied situation or even a scramble that he has already solved. Even when you are color-neutral chances of just a "star-skip" are "0".

That's not important because it never happens on other puzzles either. Have you ever seen a random 3x3 scramble and said "I've seen this scramble before"? But even if you haven't seen the scramble before or have a solved case, you can still get very easy solves. On 25-move 3x3 scrambles I've seen several cases with a solved 2x2x2 block or a 3-move xcross or something silly like that; maybe the chance is "0" to you but I've seen it, it CAN happen. And if you have much fewer possible scrambles than there should be, it's very possible that you are excluding more of the 'harder' scrambles, so you might have a higher chance of a lucky or easy case than you normally would.

The big question is if there is an (important) difference between the positions that can be reached and the positions that can't be reached.
Yes, this is an interesting question, but one that might not be able to be answered...
It is also very possible that we are excluding more of the "easier" scrambles. The super-flip on the 3x3x3 is one of those scrambles that require that maximum amount of turns (as far as we know), but I wouldn't call it a hard sramble.
Untill we know what type of scrambles we are getting and what type of scrambles we are leaving out I will trust the quality of the scrambles I have seen coming out of the 2^70 possibilities to be "hard enough" because of my experience (reality) and not because of math (theory)
I am willing to bet that if I post 10 pictures of scrambles with 70 moves and 10 pictures of scrambles with 7000 moves you couldn't pick out the "easier" scrambles without gambling

I thought there had been a discussion about always performing R++/R--, R+/R- or allowing R+/R++/R--/R- where the final conclusion was that using only R++/R-- gave better scrambles.
I tried to find that discussion, but I couldn't. Does anyone have a link?
 
(...)
I tried to find that discussion, but I couldn't. Does anyone have a link?

well, if the WCA forum would let me search, I could probably find it...

but anything I try to search gives this:
The following words in your search query were ignored because they are too common words: "any words you want".
You must specify at least one word to search for. Each word must consist of at least 3 characters and must not contain more than 14 characters excluding wildcards.

EDIT:
Searching for "Stefan" works
but not for "megaminx", "scrambling", "world record"...

EDIT 2:
http://www.worldcubeassociation.org/forum/viewtopic.php?p=1458#p1458
I think that's probably what you're looking for
 
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It is also very possible that we are excluding more of the "easier" scrambles.
That's not what I mean by "harder". I mean scrambles with a longer optimal solution and nothing more.

I am willing to bet that if I post 10 pictures of scrambles with 70 moves and 10 pictures of scrambles with 7000 moves you couldn't pick out the "easier" scrambles without gambling
If I posted 10 pictures of 7x7 scrambles with 50 moves, and 10 pictures of scrambles with 100 moves, I bet you couldn't pick out the "easier" ones either. But a computer that had the capability to find optimal solutions could, and I'd bet that a 5x5 or 7x7 scrambled with half the number of moves would be much more likely to give you very easy centers, even if they did not look easier at the start. If you took a 3x3 scrambled with (say) 12 moves you might not be able to tell it's so easy, but CubeExplorer would, and I'd be willing to bet that if you just did the cross on 100 of those scrambles you would get many more accidental corner or edge skips than you normally do.

Besides, just because you or me thinks a scramble is hard enough, does not mean it is. Even if you can't tell, maybe the pieces are in an easier position. Do five or six double layer turns on a 4x4 and see how mixed the centers look; but if you solved the centers by hand or with a computer you would find that a lot more pieces paired themselves up than normal. Another example of this: let's look at all of the corner-edge pairs on the minx and check how many face turns they are away. If the average is significantly less than the theoretical average on a random scramble (and this is not something a human could easily tell), then perhaps that scramble really is easier than normal. I would like to see someone do an analysis of this.
 
It is also very possible that we are excluding more of the "easier" scrambles.
That's not what I mean by "harder". I mean scrambles with a longer optimal solution and nothing more.
Than please say short next time. But why would we care about this in reality. Do you have a link to an optimal solver for megaminx that will reach just 1 solution this year? We are using these scrambles for speedsolving competitions, not for scientific analysis
I am willing to bet that if I post 10 pictures of scrambles with 70 moves and 10 pictures of scrambles with 7000 moves you couldn't pick out the "easier" scrambles without gambling
If I posted 10 pictures of 7x7 scrambles with 50 moves, and 10 pictures of scrambles with 100 moves, I bet you couldn't pick out the "easier" ones either. But a computer that had the capability to find optimal solutions could, and I'd bet that a 5x5 or 7x7 scrambled with half the number of moves would be much more likely to give you very easy centers, even if they did not look easier at the start. If you took a 3x3 scrambled with (say) 12 moves you might not be able to tell it's so easy, but CubeExplorer would, and I'd be willing to bet that if you just did the cross on 100 of those scrambles you would get many more accidental corner or edge skips than you normally do.

Besides, just because you or me thinks a scramble is hard enough, does not mean it is. Even if you can't tell, maybe the pieces are in an easier position. Do five or six double layer turns on a 4x4 and see how mixed the centers look; but if you solved the centers by hand or with a computer you would find that a lot more pieces paired themselves up than normal. Another example of this: let's look at all of the corner-edge pairs on the minx and check how many face turns they are away. If the average is significantly less than the theoretical average on a random scramble (and this is not something a human could easily tell), then perhaps that scramble really is easier than normal. I would like to see someone do an analysis of this.
I agree with most of the other things you say, but not with the part I bolded. Even if you would get more corner or edge skips that would only matter for blind.
My whole point is that a scramble that requires a lot of optimal moves doesn't need to be hard (again, consider the superflip). For Megaminx the chances of a scrambler messing up a scramble is much bigger than a competitor benefitting from "the easiness of 2^70" scrambles.

You should do the analysis if you are interested, but don't loose track of the practical implications.

That was indeed what I meant. I think the part that says "After the first sixty moves, there was not a single unbroken pair left." is important
 
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I am willing to bet that if I post 10 pictures of scrambles with 70 moves and 10 pictures of scrambles with 7000 moves you couldn't pick out the "easier" scrambles without gambling
If I posted 10 pictures of 7x7 scrambles with 50 moves, and 10 pictures of scrambles with 100 moves, I bet you couldn't pick out the "easier" ones either.
How much would you guys bet? How much after reading this?
http://games.groups.yahoo.com/group/speedsolvingrubikscube/message/41005
 
I am willing to bet that if I post 10 pictures of scrambles with 70 moves and 10 pictures of scrambles with 7000 moves you couldn't pick out the "easier" scrambles without gambling
If I posted 10 pictures of 7x7 scrambles with 50 moves, and 10 pictures of scrambles with 100 moves, I bet you couldn't pick out the "easier" ones either.
How much would you guys bet? How much after reading this?
http://games.groups.yahoo.com/group/speedsolvingrubikscube/message/41005

I hadn't read that before. Now I am only willing to make that bet if the inspection time is limited to .... 15 seconds (I think 60 seconds would still be good enough). But I still don't think this has any real life implications for speedsolving

I am not trained enough in statistics, but I would expect that a divergence to a limit would be the normal result as the number of moves becomes bigger. But in both MegaMinx tests it doesn't entirely work like that.

Look at what happens after 300 turns
Megaminx:
WCA Scrambler
Turns | Std Dev | Expected Std Dev | Confidence
10 |108483.94| 279 | 0.3%
50 | 21986.84| 279 | 0.9%
70 | 12559.95| 279 | 1.7% *official scramble length
100 | 5546.20| 279 | 5.0%
150 | 1451.23| 279 | 19.2%
200 | 469.90| 279 | 59.4%
210 | 398.26| 279 | 70.1%
220 | 351.96| 279 | 79.3%
230 | 312.99| 279 | 89.2%
240 | 307.22| 279 | 90.9%
250 | 294.32| 279 | 94.8%
260 | 285.37| 279 | 97.8%
270 | 280.47| 279 | 99.5%
300 | 278.30| 279 | 99.7%
400 | 275.66| 279 | 98.7%
500 | 269.56| 279 | 96.6%
1000 | 264.62| 279 | 94.8%

And this one is even weirder
Turns | Std Dev | Expected Std Dev | Confidence
10 | 91955.36| 279 | 0.3%
50 | 5529.65| 279 | 5.0%
70 | 1572.39| 279 | 17.8%
100 | 380.54| 279 | 73.4%
110 | 315.88| 279 | 88.4%
115 | 287.75| 279 | 97.0%
120 | 291.12| 279 | 95.9%
125 | 279.61| 279 | 99.8%
150 | 273.86| 279 | 98.1%
200 | 282.68| 279 | 98.8%
500 | 279.16| 279 |100.0%
1000 | 286.71| 279 | 97.4%

Are those anomalies, or is something else going on?
 
Do you have a link to an optimal solver for megaminx that will reach just 1 solution this year? We are using these scrambles for speedsolving competitions, not for scientific analysis
Okay, I give up. It looks like now you are just being a troll; we both KNOW I am right about much fewer positions being reached than normal (only one in 10^50 positions!), you just seem to be trying to convince yourself that this cannot possibly have any effect on times. Of course it can, the question is whether you are willing to do longer scrambles to have a FAIR megaminx event. After this post I am out of this discussion.

Even if you would get more corner or edge skips that would only matter for blind.
Do I need to explain how your own F2L method (working corner) works? Skipping a piece in the F2L will save time. If you do 12 random moves and solve the cross, more F2L pieces will be solved on average than normal. If you don't believe this happens, do a simulation. If you don't believe this affects times, it's because you can't solve the 3x3 quickly to save your life anyway. Ask Erik if skipping an F2L pair would make your time faster.

My whole point is that a scramble that requires a lot of optimal moves doesn't need to be hard (again, consider the superflip). For Megaminx the chances of a scrambler messing up a scramble is much bigger than a competitor benefitting from "the easiness of 2^70" scrambles.
The superflip is only easy because you know it as a pattern. Go solve it with Fridrich and see if you still think it's easy. Alternatively, go memorize ANY 20-move scramble, and imagine you get it in competition and recognize that it's your memorized scramble. Will it take you a normal 20 seconds? Of course not.
As for Megaminx scrambling, who's going to mess up a scramble now? They're ridiculously easy to execute. That's the whole reason we're using this new system. As for "the chances ... [are] much bigger", don't even TRY to compare probabilities which you have no idea about. You have no idea about either one and neither do I, and I'm not the kind of person you can convince with pseudomathematical babble.

You should do the analysis if you are interested, but don't loose track of the practical implications.
You mean "don't lose track of the fact that I don't think it has an effect", don't you? If you really want to know, let's have a fast megaminx solver do a long session with someone else scrambling, where they randomly do scrambles from the Pochmann and Jaap scramblers and see if there is a difference in the average times. It doesn't matter if you don't THINK there is no effect, the only way to prove there isn't is to actually test it.

That was indeed what I meant. I think the part that says "After the first sixty moves, there was not a single unbroken pair left." is important
Unbroken pairs are irrelevant. They just make the puzzle look more scrambled. The 3x3 scramble M E S breaks EVERY corner-edge pair, but is it an easy scramble? Of course. You have to take into account how many moves it takes to join the corner and edge together again. I would not be surprised if an abnormally large number of pairs are just one or two face turns away with this scrambling scheme.

so, what's the conclusion?
is his "method" correct? do we need 250+ moves with the current scrambler?
If you want to even have a chance of getting to every position, you need at least ln(1.007 * 10^68)/ln(2) = 226 moves counting cube rotations. I'm not sure it is necessary to do this, but I do think we should check to see exactly how scrambled our "scrambled" megaminxes are. For complicated puzzles like this, positions which look scrambled can still be much easier than average.



P.S. Arnaud, I don't know what's come over you, but you used to be a LOT nicer. I see you being argumentative for no reason, and criticizing people who say "7x7" instead of "7x7x7"... what's wrong? This is NOT the Arnaud I know. I'm having a really bad day today, what's your excuse?
 
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