The FMC thread

Discussion in 'General Speedcubing Discussion' started by blah, Jul 12, 2009.

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  1. blah

    blah brah

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    So I started FMC 2 weeks ago because of the forum competition, and it's the funnest (note: not funniest) thing in cubing for me by far and nothing comes close :D (well, maybe big cubes BLD, which I've quit :p)

    But being a noob and all in FMC (only 6 attempts so far), I couldn't find a place on this forum for me to ask questions about FMC. I believe many would agree that too many speedcubing questions are over-asked in this forum, but I've only ever seen a handful of threads about FMC, hence this thread.

    I'd love to read and learn from a lot of good and elegant solutions from the pros here.

    ----------

    I'll start off with a question I hope the experts here can help me with:

    Scramble: U2 R F2 D2 B2 D2 F2 L2 R F2 L U2 B U' B' U2 L2 F' L2 B U2 (21f)

    Premove + (Scramble)': D' + U2 B' L2 F L2 U2 B U B' U2 L' F2 R' L2 F2 D2 B2 D2 F2 R' U2
    2x2x2: R L' D' (3/3)
    Triple x-cross: R' U' B D B2 D2 R2 D B R' (10/13) (EO skip)

    13 moves at this stage is very good for me, so I don't want to give up this good start. But, now what?

    I see a few ways to end this, but none of them are nice:

    Permute remaining edges: (cancelled: R) U2 R' U R U' R' (6/18)
    OLL: L' U R U' L U R' (7/25)
    PLL: B2 L2 B R B' L2 B R' B (9/34)
    Undo premove: D' (1/35)

    or

    (Different) triple x-cross: R' U' B D B2 D' B R' B' R B (11/14) (EO skip)
    Permute remaining edges: U' F' U2 F (4/18)
    Remaining corners suck

    or

    (Different) triple x-cross: R' U' B D B2 D' B R' B' R B (11/14) (EO skip)
    Finish off F2L: U F' U' F U' F' U F (8/22) (OLL skip)
    PLL + AUF: L2 U F' B L2 F B' U L2 U2 (10/32)
    Undo premove: D' (1/33)

    So, how would YOU end this? I'd like to see how you guys handle this bad ending.
     
    Last edited: Jul 12, 2009
    Dr_Detonation likes this.
  2. Tim Reynolds

    Tim Reynolds Premium Member

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    Looking back at your first ending, have you tried doing an insertion instead of an A perm? At worst that's 8 moves=34 total, but there's a good chance you'll find an insertion with a cancellation. I'll keep looking a bit more, but that's my first idea.

    Here's another ending for the first solution, one more move but it'll give you another place to look for an insertion:
    F2L ending: (cancelled R) U2 R' U2 R U2 R'
    OLL: (R U2 R2) U' R2 U' R2 U2 R
    AUF, then left with 3 corners.

    Also you can try for an insertion on the third solution instead of the U perm, but edge insertions usually don't save many moves over U perms.

    For the third solution, that's not all that bad--either (URF URB LUB)(URF RDF UBL) or some other combination of 2 3-corner cycles. That's lots of places to look for insertions--probably would end up at about 32 moves.

    I'll start looking for some insertions, see if I find anything good.
     
    Last edited: Jul 12, 2009
  3. soccerking813

    soccerking813 Member

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    Just a question about FMC. Why can you pretty much use a different scramble than what is given? Like, why are you allowed to use the scramble inverse and premoves and stuff? It seems like that ruins the idea of solving any situation in as few moves as possible.
     
  4. blah

    blah brah

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    Hmm. Never thought about it from that "conservative" point of view before :rolleyes: I've always thought the guys who came up with the inverse scramble and premove ideas were geniuses, they're just so simple, so elegant.

    But anyway, I think you're right about solving the inverse scramble being solving a "different" scramble. But I have to disagree with you about premoves. Of course you can solve the same scramble without using premoves, it just takes a lot of concentration to know which piece is supposed to go where. Why make life harder when you can just use premoves?
     
  5. blah

    blah brah

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    I thought I read somewhere that insertions generally aren't recommended in competitions due to the time constraint? That's why I haven't been taking it seriously at all. I wouldn't know where to start anyway. Do you really go turn by turn to look for an insertion point with cancellations? Isn't that very time consuming? :eek:
     
  6. Johannes91

    Johannes91 Member

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    Inserting one commutator takes me just a few minutes or so (or took, I haven't done that in ages). Inserting two optimally takes a bit longer, but at least quickly looking for really nice cancellations is a good idea.
     
  7. Tim Reynolds

    Tim Reynolds Premium Member

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    It turns out that you can do that A perm in the first solution in 6 moves. What's really nice is that the insertion is before the first move of the solution, so it's the first thing you'll see.

    (before first move) U R D' R' U' R D R' (R' cancels R in 2x2x2)

    You're allowed to use stickers in competition, so sticker the pieces that you're using for the insertion. Scramble, start doing the solution. Often you'll look at a case and know that there's no 8-move solution, ignore that position and just keep going. It doesn't take all that long, and with practice is very fast. Doing 2 might take longer, yeah, but 1 is pretty quick.
     
  8. Swordsman Kirby

    Swordsman Kirby Member

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    A single insertion takes me two minutes maximum to find. It's really not that hard once you get the hang of it. :p
     
  9. fanwuq

    fanwuq Member

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    Inverse scramble: invert your solution to your inverse scramble and you have just solved the given scramble. So I think that's OK for non-linear FMC, but I almost never use inverse scramble anyway; it just takes too much time.

    Premoves: I don't think you know what is a premove. It only makes mismatched blocks look easier. That is all. I've used pseudo blocks during linear FMC and it's not that hard. You don't steal any moves since you have to undo it at the end of your solution anyway. I probably will just deal with the the recognition at competition, but when I have a computer; I abuse it on alg.garron.us. ;)

    They are clever techniques and you do have to submit the true solution to the scramble given at the end of the day any way.
    You might want to look into linear FMC, where you can't undo any moves. Still can use pseudo-blocks, but not premoves for them to look easier.


    Blah,
    I did not look much into this, but I would have just did Niklas after solving all edges and inserted an A perm. I haven't seriously tried multiple insertions yet, but I do 1 insertion in about 5-10 minutes without the use of post-it stickers. I just write down all the sticker cycles and look at what I wrote down every single move.
    For example:
    RGY-->
    RYB-->
    RBW
    I write that down go through every move of the solution and keep close attention if any of stickers of a column line up like RGY and RBW or RGY and RYB.
     
  10. blah

    blah brah

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    Premove + scramble: R2 F2 + L2 D L2 U F2 L2 D B2 D' B2 L2 D' B L B F U2 B' L2 D U2 (21f)

    My shortest solution so far, I'm not happy with it yet:

    Solution (A)
    2x2x3: D F' R' U F' R' B F' (8/8)
    Triple x-cross: B F' L D' L' D F L' B' L (8/16)
    Orient remaining edges: U' F U' F' (4/20)
    Permute remaining edges and 2 corners: U L' U2 L U2 (5/25) (I don't consider this lucky because I did lots of trial and error to get this)
    Undo premove: R2 F2 (2/27)
    Corner commutator: F' D2 F U F' D2 F U' (7/34)

    (Gray = cancelled moves.)

    ----------

    Other good starts:

    Solution (B)
    2x2x3: D F2 R' F' U' B L2 (7/7)
    Stuck.

    Solution (C)
    2x2x3: D F' R' U F' R' B F' (8/8)
    Solve random blocks: U F U F' L' B L B' L2 U2 (10/18)
    Stuck.

    Solution (D)
    2x2x3: D F' R' U F' R' B F' (8/8)
    Solve random blocks: U F U F' L' B L2 B' L U2 (10/18)
    Stuck.

    Questions:
    1. For solutions (C) and (D), is it ever a good thing to have permutation parity at the end? If not, is there a quick fix to this?
    2. Am I over-using premoves? Currently I seem to decide to do premoves as soon as I see a pseudo-2x2x2 block.
    3. For corner commutator insertions, is a single move cancellation usually good enough? Or should I try harder to look for 2 move cancellations? How often will I get 2 move cancellations, i.e. once in how many solves?
    4. For corner commutator insertions, is it generally advisable to insert in the middle of a double turn? I hope you understand what I mean by this, I don't really know how to phrase it properly.
    5. Is doing 3 (or more) premoves ever advisable?
    6. What do you consider a "good" number of moves for the 2x2x3? I haven't done much FMC yet, but so far I seem to average sub-10, which I think is pretty decent. But I almost always suck after building my 2x2x3 :eek:
     
    Last edited: Jul 13, 2009
  11. blah

    blah brah

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    Thought I'd share this beautiful solution :) Anyone else got elegant solutions to share?
     
  12. fanwuq

    fanwuq Member

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    1. It is bad, and I don't know how to fix it. Sometimes I random fix it or if I run out of time, just do a 1LLL with classic pochmann and get a solution around 36 moves.
    2. If you are just solving by yourself and could use something like alg.garron.us, use as many premoves as you wish, but I never used more than 3. Usually I can have a solution around 32 with at most 1 premove. At competitions, I don't recommend them at all, but if you must, do only 1.
    4. ??? You mean R (commutator) R? I do not use either and don't see the point and I think R (commutator) R would be equivalent to R2 (commutator) or
    (commutator) R2 depending on where is the cancellation..
    5. No, you are crazy. You might as well as finish the whole solve using only premoves. :p Wait... you might as well as use the inverse scramble.
    6. Your 2x2x3 blocks are very good, but that's probably because this is a fairly easy scramble. I general get around 10 moves each time, but there are plenty of hard scrambles that I can't get sub-12 even after 20 minutes.
     
  13. JLarsen

    JLarsen Premium Member

    Is there some kind of resource that explains some FMC concepts? I've searched for stuff like premoves and insertions, and I've come up with nothing. Any recomendations?
     
  14. blah

    blah brah

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    As far as I know, there aren't any guides/explanations/tutorials for premoves, at least I've never seen one. I read about it about a year ago (I think) in Arnaud's FMC thread. I can't locate the thread now (found it), but all he provided was an example solve without explaining how or why it worked, so I didn't understand it at all back then.

    But I finally understood premoves about a week ago after messing with my cube for hours and hours, but I'm sure you'd take a much shorter time to grasp the concept :) IMHO, it's not hard at all to know how and when to use it; but to know why it works the way it does, all it takes is a little extra thinking, it's completely intuitive :)

    Every who got into FMC seriously seems to know what premoves are, and I can only assume they all figured it out on their own, so I believe anyone else can too if they're serious about FMC. Wouldn't a tutorial just spoil all the fun? FMC is probably the only thing left in speedcubing that's unharmed by guides for "Dummies who just want to know how but not why".

    As for insertions, it's just jargon. You don't have to "learn" anything to be able to do it (well, maybe commutators if you don't already know). You just need experience to be good at it. Here's what an insertion is: Say you get an A-perm for PLL, that's gonna cost you 9 moves. But there's bound to be some point within your solution in which those 3 corners are solvable using only an 8-move commutator. So you cycle those corners in the middle of your solution to save a move, get it? If you get a cancellation or two, you'd effectively be doing 6 or 7 moves to cycle 3 corners instead of 9 moves.
     
    Last edited: Jul 13, 2009
  15. blah

    blah brah

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    Roux for FMC

    What's a good number of moves for the first two 1x2x3 blocks for Roux? I did two solves and got 18 (7+11) and 17 (4+13), and I don't think it's good at all.

    I'd attempt Roux if I get a nice 1x2x3 (<7 moves) but couldn't get a short sliced 1x1x3 (doesn't matter if the colors are matched or mismatched), is this a good approach? What would you guys do in this case?
     
  16. blah

    blah brah

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    Crazy solution with 10 move cancellations (no premoves, no inverse scramble)

    Scramble: D2 L D2 L D2 U2 R B2 R U R D R F' R2 B L' D' L2 B U2 (21f)

    2x2x2: L' U' L' D' B (5/5)
    Siamese 2x2x2s: F2 R2 F . R F R2 F' (5/10)
    3rd F2L slot: D2 U L' U2 L D2 (6/16)
    4th F2L slot: F R U2 R' F' (3/19)
    Pseudo-OLL: F R U' R' U' R U R' F' (6/25)
    AUF: U2 (1/26)
    Insert at .: F' R2 F L F' R2 F L' (5/31)

    Solution: L' U' L' D' B F' L F' R2 F L' R F R2 F' D2 U L' U2 L D2 F R U R' U' R U R' F' U2 (31)

    This is only my tenth or so FMC attempt, so 10 cancellations is just ridiculous to me :eek: :eek: :eek: Or am I just overreacting? :eek: How many cancellations do you guys usually get per solve?
     
  17. Mike Hughey

    Mike Hughey Super Moderator Staff Member

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    I've only had that many moves cancel a couple of times. But then, you're clearly already a lot better than me. Frustrating. :)

    I guess it makes sense that you're good at this, considering all the cube theory you've been interested in all along. Congratulations on some good solves.
     
  18. JLarsen

    JLarsen Premium Member

    Oh man blah, this is your new thing. I see it. You did BLD before if I'm not mistaken, and BLD wasn't really my thing, and neither is cube theory. My grasp on commutators is minimal. I think I'll just leave this event alone.
     
  19. fanwuq

    fanwuq Member

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    But real men do Petrus FMC!
    You only need minimal 8 mover commutators for FMC. BH is not necessary at all, so you don't need to learn anything. Just your nice block building alone will get you plenty of sub-40 solutions.
     
    Lars Petrus likes this.
  20. JLarsen

    JLarsen Premium Member

    Erik has tried to get me into fmc, and I think I'm pretty bad at it. I most certainly don't think I could sub 40 with standard oll pll right now, but I haven't really tried. I'll give it a go I guess...

    Edit I tried making 2x2x3 blocks and my first two tries were 11 and 10. Is that good?

    Scramble: F2 D' B' R' D U' R F D2 B F R2 B2 F' D' R D U' B2 D' U R B2 R' U2

    2x2: y' by mistake.....U' B2 D' L D2

    EJ 2X2X3 expansion(not sure if i should use that in fmc)

    B' U R U R2

    10 moves

    EO: y2 R' F R

    13 moves

    ha i think i messed up writing my annotation i suck....there i think i got it right now...

    I really am not sure what to do now, but i'll keep going....

    Step 4a: y' U' R U2 R2 gives you another EJ pair....lol I have no idea....

    oh man this is were it gets bad....yeah I'm just going to stop there I'm not going about this right. I'll do 4a without another ej pair i don't know enough to do that.

    New Step 4a....wow...and actually step 4b too:

    R U' R' U R U R2

    Alright that puts me at 20 moves for a....f2l of sorts....but now I have no idea what to do besides fix an ej pair, or change my 4a solution to break it before hand so i can do cls and pll.

    Another step 4a with what I said before....

    R U' R' U R U R' U' R' gives me 21

    Step 4b: U' R U2 R' U R U' R' leaves me with the wost cls case in existence....

    Okay I'm just going to break apart the steb 4b pair differently and go with the ll that I get here's my final crap solution:

    Scramble: Scramble: F2 D' B' R' D U' R F D2 B F R2 B2 F' D' R D U' B2 D' U R B2 R' U2

    2x2: y' U' B2 D' L D2 (5)
    2x2x3: B' U R U R2 (10)
    EO: y2 R' F R (13)
    Step 4a: y' R U' R' U R U R' U2 R' (22)-Ruined it, crap from here on.
    Step 4b: U R U' R' U R U R' (30)
    Cls: y' R U2 R' U R U' R' U R U R' (41) -God dammit
    R perm: y' R U2 R' U2 R B' R' U' R U R B R2 (54)

    My blockbuilding is fine....but I just have no clue after that. At least I wrote down the solution correctly. (I think)

    Anyway that was kind of fun. I think I have potential, although I'd love some advice.
     
    Last edited: Jul 14, 2009

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