[Help Thread] FMC Discussion

[Jaycee]

post

Thanks ! For the current round on http://fmc.mustcube.net/ , I have a 22 move skeleton leaving, again, 4 corners, one of which is a twist.

F B U2 B2 U B' L2 B2 F2 R2 D' F' L' F' U' R' B2 L U' F2 D B2 F' R2 F2 D2 F2 B2 R' F2

Spoiler

L U' L2 D' F' R F' // 2x2x3
U' L U2 B2 U' // EO
L B2 L B L2 B' L2 B2 L B' // leaves 4 corners

I'm leaving the house for a bit so I'm just posting this here to save my progress.

 

[Pyjam]

I'm leaving the house for a bit so I'm just posting this here to save my progress.

Seriously ?

 

[cubernya]

Figured I should post this here as well. WARNING: CURRENT COMPETITION IN SPOILERS

Spoiler

Also, my FMC notes/explaination (the result itself is on the site; red was not written at first)

Spoiler

z
U2 L' F' B' L D R B' R2 B' D2 B2 // F2L-1 (12/12)
y' R U R' U // Leaves 3 corners (4/16)
F2 L' B' L F2 L' B L // L3C commutator (8/24)
RYB -> OYG -> WGO // Commutator cycle (for searching for insertions)


R2 F2 L B2 R' F2 L D2 R' B2 U B D' B' F R' F2 U R2 U' scramble

Rotationless:
L2 D' F' B' D R U B' U2 B' R2 B2 // F2L -1 (12/12)
F L F' L // Leaves 3 corners (4/16)
D2 B' U' B D2 B' U B // L3C commutator (8/24)

~45 min solution, and very nice I must say (it's my PB)
No insertions for the L3C though If you can find any, please show it! (if it cancels moves)

Copied strait from thread. If you have any suggestions, please post.

Anybody?

 

[guusrs]

Anybody?

I tried insertions on your skeleton, but you're right no cancellations! 8 move insertion is optimal. Well done!

But this turns out to become a very interesting scramble, have a look at the solve I just posted in the weekly competition forum!

 

[nickvu2]

Anyone willing to help me figure out what I’m doing wrong? This is my 2nd time using NISS, so I'm still getting comfortable with it.

Scramble: R2 F2 L B2 R' F2 L D2 R' B2 U B D' B' F R' F2 U R2 U' (from Week 5 of the weekly competition)

Spoiler

2x2x1: F L F2
switch to solved cube
Pre-moves: F2 L’ F’ + [inverse scramble]
continue with F2L-1 & EO: F U F’ U’ R F’ R U F U2 F2 R’ F’ L’
switch to solved cube
Pre-moves: L F R F2 U2 F’ U’ R’ F R’ U F U’ F’ + [regular scramble] + F L F2
continue with Last Slot & EP: U2 R2 U R2 U2 R2

Disregarding the last 3 unsolved corners, shouldn’t this be my solution so far?
(F L F2) (U2 R2 U R2 U2 R2) (L F R F2 U2 F’ U’ R’ F R’ U F U’ F’)
But that doesn’t leave me with the 3 unsolved corners.

Where am I messing up?

 

[Mike Hughey]

Spoiler

(F L F2) (U2 R2 U R2 U2 R2) (L F R F2 U2 F’ U’ R’ F R’ U F U’ F’)
But that doesn’t leave me with the 3 unsolved corners.

Where am I messing up?

Spoiler

You need to go ahead and add the AUF before adding the premoves, so:
(F L F2) (U2 R2 U R2 U2 R2) U (L F R F2 U2 F’ U’ R’ F R’ U F U’ F')

Note that this changes which three corners are unsolved.

 

[kinch2002]

Anyone willing to help me figure out what I’m doing wrong? This is my 2nd time using NISS, so I'm still getting comfortable with it.

Scramble: R2 F2 L B2 R' F2 L D2 R' B2 U B D' B' F R' F2 U R2 U' (from Week 5 of the weekly competition)

Spoiler

2x2x1: F L F2
switch to solved cube
Pre-moves: F2 L’ F’ + [inverse scramble]
continue with F2L-1 & EO: F U F’ U’ R F’ R U F U2 F2 R’ F’ L’
switch to solved cube
Pre-moves: L F R F2 U2 F’ U’ R’ F R’ U F U’ F’ + [regular scramble] + F L F2
continue with Last Slot & EP: U2 R2 U R2 U2 R2 U. You missed this move out

Disregarding the last 3 unsolved corners, shouldn’t this be my solution so far?
(F L F2) (U2 R2 U R2 U2 R2) (L F R F2 U2 F’ U’ R’ F R’ U F U’ F’)
But that doesn’t leave me with the 3 unsolved corners.

Where am I messing up?

See spoiler

 

[nickvu2]

Great, thanks guys! Are you able to explain why AUF is required for it to work? Every other step of the way, I feel like I stopped at arbitrary points and the block remained intact.

 

[okayama]

Great, thanks guys! Are you able to explain why AUF is required for it to work? Every other step of the way, I feel like I stopped at arbitrary points and the block remained intact.

NISS is a trick based on premoves technique. If you want to understand NISS,
you have to understand premoves first. My post may help for that.
In my explanation, ... doesn't anything to the cube is quite important.

Once you understand why premoves work, you may understand why NISS works,
and why AUF is required in your solve.

As a related topic, see also Kryptonite's post.

 

[Mike Hughey]

Thanks, okayama - I had started typing a response to Nick, and realized that it just got too involved and I didn't have time, so I gave up. Your previous post is a great way to understand premoves. Nick, definitely read his post link above. Then also note that in your partial solution, since you left 3 corners unsolved, the 3 corners move around when you move the premoves to the end. That's because you didn't completely solve it.

Sometimes I find that an interesting way to look for insertions; you can either look for the insertions before you piece the whole solve together, or if you're having no luck with it, you can go ahead and put the premoves at the end and look for an insertion with that set of pieces. Odds are they're related somehow that I don't understand (so theoretically, it's probably no better), but I do know that I've had cases where I couldn't find a good insertion before adding the premoves on the end, but then if I added the premoves on the end, I was able to find a decent insertion - even if it didn't make better cases (I suspect that, although I don't know that), it did make something easier to find.

(I hope that made sense. It's so hard to talk about FMC in text.)

 

[Cubenovice]

Regarding premoves before scramble or at the end of the solve to find your corner cycles:
It will be different pieces to look for but the net result will be exactly the same
You will find the same cycles.

I always correct the premoves first and only then sticker the remaining corners.
This enables you to explore the full solution.

Extreme example:
If you would have 8 premoves and then look for insertions without correction you have 8 moves less to check...

 

[Mike Hughey]

It will be different pieces to look for but the net result will be exactly the same

I suspected this might be true, but I hadn't tried to figure it out to see if it really was or not. Anyway, as you say, you get the whole solution to look through if you correct the premoves first, so that's a good reason to go that way.

 

[Pyjam]

In both cases, the pieces are at the same relative positions. They show different stickers however.

Theoretically, it's possible to have more than 8 cancellations after an insertion. If someone have an actual example, I'll be happy to see it.

 

[irontwig]

All that means is that you have a crappy skeleton, though.

 

[Pyjam]

I think so. But in case I'm wrong, I wrote here to ask for an actual example.

 

[irontwig]

A=Leaves three corners B=Optimal solution to scramble

A.

Insert A' B at dot to cancel a crap ton of moves.

 

[Pyjam]

It's not exactly what I ask.

 

[okayama]

In both cases, the pieces are at the same relative positions. They show different stickers however.

Theoretically, it's possible to have more than 8 cancellations after an insertion. If someone have an actual example, I'll be happy to see it.

I got 9-move cancellation by a corner 3-cycle insertion at Weekly competition 2010-21.
Does this answer you?

 

[Pyjam]

Thanks Okayama. You did it! You're amazing.

However, in your example, correct me if I'm wrong, I see only 6 cancellations at the insertion point : L [R D R'] + ([R D' R'] U2 R D R' U2) + F2 D' F'

I once got 9 moves cancelled (for a grand total of 13 for the last layer), but it was COLL Pi + PLL U, not a 3-corner cycle :
…U2 L2 [U' L] = end of F2L
+
[L' U] R U' L U' R' [U' R U' R'] = COLL Pi
+
[R U R' U R'] U' R2 U' R' U R' U R U2 = PLL U

Well, 16 moves remaining (for last layer) is almost as long as your usual solutions.

 

[Cubenovice]

Pyjam, you should read more lines

...L'
L ...