[Help Thread] FMC Discussion

Brest said:
You should find that any insertion made within the part of the solution that you have already checked will still work. It will not matter if the premoves are before the scramble, or at the end of your solution, just as long as those moves are still within the sequence. Some (or all) of the unsolved cubies will likely be different colours, however their position within that part of the solution will be the same.
Click to expand...

I think you missed Cubenovice's point.

In the example, if you use the scramble with premoves, you will find you need to cycle (ULF,BLU,RDB,DFL,RFD) at the end of the skeleton. If instead, you don't apply the premoves before the scramble, but apply them after the skeleton moves, you find you need to cycle (UFR,BUR,BRD,DFL,LUB).

If you were to put stickies on the cube to look for insertions to solve (ULF,BLU,RDB,DFL,RFD), but then apply the scramble without premoves, the insertions you find will be for cycling the wrong pieces. You will be cycling(ULF,BLU,RDB,DFL,RFD) when you need to be cycling (UFR,BUR,BRD,DFL,LUB).
 
cuBerBruce said:
I think you missed Cubenovice's point.

In the example, if you use the scramble with premoves, you will find you need to cycle (ULF,BLU,RDB,DFL,RFD) at the end of the skeleton. If instead, you don't apply the premoves before the scramble, but apply them after the skeleton moves, you find you need to cycle (UFR,BUR,BRD,DFL,LUB).

If you were to put stickies on the cube to look for insertions to solve (ULF,BLU,RDB,DFL,RFD), but then apply the scramble without premoves, the insertions you find will be for cycling the wrong pieces. You will be cycling(ULF,BLU,RDB,DFL,RFD) when you need to be cycling (UFR,BUR,BRD,DFL,LUB).
Click to expand...

I've read many of your posts so I know that you have more experience and knowledge about the cube than I do. So, hopefully, I'm not making a fool of myself, but if so then I'll learn something. =)

I believe I understand what Cubenovice was expressing, and also what you have posted. However, while learning these techniques, I did this on purpose in the hopes to have two different solutions to find insertions within. It didn't work how I wanted it to, as each insertion I found with premoves before the scramble were the same as those found with premoves after the skeleton's solution.

For example, the same solution Cubenovice posted:

1st insertion:
Premoves before scramble
(F' R2)
B2 D U B R' D2 B L2 D B2 U2 R F U2 D' F U2 B2 L' D' F' U2 L2 R2 F
R D' R
U R2
U' F2 U2 F2 U2 F' U @
Insert at the end: [F',DBD']
alg.garron.us
Which leaves 3 corners

Premoves after skeleton
B2 D U B R' D2 B L2 D B2 U2 R F U2 D' F U2 B2 L' D' F' U2 L2 R2 F
R D' R
U R2
U' F2 U2 F2 U2 F' U @
(F' R2)
Insert [F',DBD'] at the same spot, which is after undoing the premoves.
alg.garron.us
Also leaves 3 corners
Each time the same insertion works at the same place within the solution.

2nd insertion:
Premoves before scramble
(F' R2)
B2 D U B R' D2 B L2 D B2 U2 R F U2 D' F U2 B2 L' D' F' U2 L2 R2 F
R D' R
U R2
U' F2 U2 F2 U2 F' U
F' D B D' F D B' D' #
Insert at the end: [L',UR'U']
alg.garron.us
Solved cube

Premoves after skeleton
B2 D U B R' D2 B L2 D B2 U2 R F U2 D' F U2 B2 L' D' F' U2 L2 R2 F
R D' R
U R2
U' F2 U2 F2 U2 F' U
F' D B D' F D B' D' #
(F' R2)
Insert [L',UR'U'] at the same spot.
alg.garron.us
Also solved
As long as the premoves are used, either before the scramble or after the skeleton, then each insertion found with one sequence will work at the same spot within the other sequence. The only place a 'new' insertion could be found is within the actual premoves themselves.

The solution is different, so therefore the unsolved corners will be different at the end. I have been presuming that this is 'undone' or 'fixed' after the premoves are inversed, as you step back through the sequence looking for an insertion. Maybe that presumption is incorrect?

If what I'm posting here is wrong, then I don't understand what is being expressed, which is fine by me. I still have much to learn and this can be the next thing I learn. Can you explain why the insertions I've used in these examples work within each solution the way they do? And if this is different to the one Cubenovice found, could you also explain why it is different?
 
Brest said:
As long as the premoves are used, either before the scramble or after the skeleton, then each insertion found with one sequence will work at the same spot within the other sequence. The only place a 'new' insertion could be found is within the actual premoves themselves.

The solution is different, so therefore the unsolved corners will be different at the end. I have been presuming that this is 'undone' or 'fixed' after the premoves are inversed, as you step back through the sequence looking for an insertion. Maybe that presumption is incorrect?

If what I'm posting here is wrong, then I don't understand what is being expressed, which is fine by me. I still have much to learn and this can be the next thing I learn. Can you explain why the insertions I've used in these examples work within each solution the way they do? And if this is different to the one Cubenovice found, could you also explain why it is different?
Click to expand...

What you're saying is basically correct. I wasn't claiming what you were saying was wrong.

As you noted, if (starting with a solved cube) you apply:
premoves, scramble, skeleton
you will end up with different unsolved corners (typically) than if you apply:
scramble, skeleton, premoves

Therefore when applying stickies to your cube to label which pieces must be cycled, you must be aware of which case of the above two cases you use. When going through the skeleton moves to find insertions, you must use the same case for which you applied the labels. If you don't, you cycle the wrong pieces, and that is what I understand is the error Cubenovice made. It's an easy mistake to make, and I know I've made that mistake myself more than once. Some people just walk through the skeleton backwards (as perhaps you do, it sounds like) rather than solve, scramble, and walk through the skeleton forward.
 
cuBerBruce said:
What you're saying is basically correct. I wasn't claiming what you were saying was wrong.

As you noted, if (starting with a solved cube) you apply:
premoves, scramble, skeleton
you will end up with different unsolved corners (typically) than if you apply:
scramble, skeleton, premoves

Therefore when applying stickies to your cube to label which pieces must be cycled, you must be aware of which case of the above two cases you use. When going through the skeleton moves to find insertions, you must use the same case for which you applied the labels. If you don't, you cycle the wrong pieces, and that is what I understand is the error Cubenovice made. It's an easy mistake to make, and I know I've made that mistake myself more than once. Some people just walk through the skeleton backwards (as perhaps you do, it sounds like) rather than solve, scramble, and walk through the skeleton forward.
Click to expand...
Ah, of course that makes sense. I didn't look at it in that way.
 
Nice discussion!

Looking back at it I should not have made this mistake!!!
I had already found out that the remaining corners change in a NISS solve.
So whenever I have a NISS solve leaving some corners I first "correct" my solution and only then sticker the pieces.

Offcourse this is no different for a regular solve with premoves...

BTW:
With the 1 move 2x2x2 on nlcuber's scramble; should we consider this a lucky scramble?
I ran it through CE to check if there was an abnormal short solution and guess what? Optimal is still 18 HTM
 
irontwig said:
Three unique 22s (although using the same F2L-1):

http://fmc.mustcube.net/results.php?round=348&format=official&metric=htm
Click to expand...
You are doing PB every week :)
Congratz for all three solution, and Okayama’s classic 20 moves solution!
My belated solution below:
Scramble: B2 L' F2 D F' B R D U' B R' D2 R' F' R' F' L2 F D L' R2 F B' R U2 D R2 B2 U' F2
Solution: B’RL’U2R’L’DF’L2R2UR2B2D’U’L’D’BF’RDLU2D2L2UD’ (27 moves)
B’F2 .L2DF’ Guimond 1. step,
L2R2 more 2 edges,
UR2B2D all corners and 6 edges,
edges insertion: .F2MF2M’ 3 moves cancel,
D2U’L’D’BF’RDLU2D2L2UD’ L5E.
 
My first solution with that start matched Irontwig's. I tried inserting the pair cycle but nothing cancelled (if only the cycle when the other direction!)

Then I found:

F2L-1: L R2 B2 R' D R U' R2 (8/8)
Connect some stuff: L' B2 R B R' (5/13)
Restore: U2 B L (3/16)
3-cycle: L' B' L F L' B L F' (8/24-4)

Cancels 4 moves resulting in 20. Guus your solution seemed to finish so similar to this one. Perhaps if you had found the 8-move start sooner you might have found this as well!
 
Is there a website where I can find an explanation for the rules of FMC and how it works?
Because I see all these things like premoves and insertions and other things I've never heard about, and I'd really like to know what it all means :)
 
JonnyWhoopes said:
What would be a good solution for this scramble?
D U2 L2 B L' U R U2 B' R2 B2 F2 D' L B2 U2 D F2 B L B2 D' B U' R'
Click to expand...

R2 D2 B' U F' B' L' B D' B2 F U' F2 R2 D R' U' R D' R' U2 R' U' F' U B D' L D' (29)


R2 D2 B' U [Square+2 pairs]

Switch to inverse:
D L' D [Roux block+Square]

Switch back to normal:
F' B' L' B D' B2 F2 [Pseudo F2L-1]
F' U' F [Pseudo F2L]
F R.U R' U' F' U [LLEF+1]
B [Undo pseudoness]
D' L D' [Undo premoves]

Insert at dot: R D R' U' R D' R' U (Two moves cancel)
 
You must log in or register to reply here.

Similar threads

P
Weekly 22-49 FMC Speed Solve 1 Solutions
Replies
0
Views
982
PiEquals3.14
P
R
Heise Method Discussion thread
10 11 12
Replies
238
Views
67,540
abunickabhi
abunickabhi
C
[NR] [CR2, WR3] Nachuan Sun 19.67 FMC Mean
Replies
5
Views
687
abunickabhi
abunickabhi
OtaMota
[AsR] Jaehyun Jeong 19.33 FMC Average and 17 FMC Single
Replies
17
Views
1,366
OtaMota
OtaMota
AJT17
[SAR] Brayan Alexander Sandoval Camacho 21.33 FMC mo3
Replies
3
Views
511
acrystal
acrystal
Back
Top