[Help Thread] FMC Discussion

[porkynator]

From fmc.mustcube.net round #456 (running contest)
Scramble: U2 L2 R' F L2 R2 D L F B2 R F2 L2 U2 L2 U' B' D U B L2 U D2 F B' R' U2 L D' U'

Spoiler

Easy scramble in my opinion, but I liked my solution so much that I wanted to post it somewhere.
Plain Heise solution with a 3-cycle inserted:
F R2 //2x2x1 (2/2)
U' B2 F//2x2x3 (3/5)
U' R2 U' F R F' //F2L+EO (6/11)
U * F' U F //Make 2 CE pairs (4/15)
U' F' U2 F U' //All but 3 corners (5/20)
* = U B U' F2 U B' U' F2 //Inserted commutator, 2 moves cancel out (6/26)

 

[TheNextFeliks]

From fmc.mustcube.net round #456 (running contest)
Scramble: U2 L2 R' F L2 R2 D L F B2 R F2 L2 U2 L2 U' B' D U B L2 U D2 F B' R' U2 L D' U'

Spoiler

Easy scramble in my opinion, but I liked my solution so much that I wanted to post it somewhere.
Plain Heise solution with a 3-cycle inserted:
F R2 //2x2x1 (2/2)
U' B2 F//2x2x3 (3/5)
U' R2 U' F R F' //F2L+EO (6/11)
U * F' U F //Make 2 CE pairs (4/15)
U' F' U2 F U' //All but 3 corners (5/20)
* = U B U' F2 U B' U' F2 //Inserted commutator, 2 moves cancel out (6/26)

Nice. Mine was like 31 moves. But really nice scramble I agree. Can't wait to see Okayama's solution.

 

[irontwig]

Found a 24-mover quickly, but got bored of trying to find something super lucky after half an hour.

 

[TheNextFeliks]

Ok. Whenever I do fmc, I usually do f2l-1 then orient and place edges. Then I do 2 insertions. I have found this to be very inefficient. I can sometimes do an f2l-1 in about 12. Then next step takes about 12 also. Then two insertions 16 usually cancel 2-4 so 14-16. This proves to be very inefficient. Any tips for better continuing from a 2x2x3 or f2l-1?

 

[Jakube]

Try to orient edges during F2L-1. And try to improvise, do not always use the same approach!

 

[irontwig]

Ok. Whenever I do fmc, I usually do f2l-1 then orient and place edges. Then I do 2 insertions. I have found this to be very inefficient. I can sometimes do an f2l-1 in about 12. Then next step takes about 12 also. Then two insertions 16 usually cancel 2-4 so 14-16. This proves to be very inefficient. Any tips for better continuing from a 2x2x3 or f2l-1?

F2L-1 in 12 is great, kinda doubt you average that though. You don't have to orient edges first (or even just leave corners). Try pairing up any CE-pair and make a (pseudo) F2L and see if you can leave few enough pieces with few enough moves or even solve everything if you happen to know the LL case. Also try to insert moves earlier and see if that makes finishing off easier.

 

[TheNextFeliks]

F2L-1 in 12 is great, kinda doubt you average that though. You don't have to orient edges first (or even just leave corners). Try pairing up any CE-pair and make a (pseudo) F2L and see if you can leave few enough pieces with few enough moves or even solve everything if you happen to know the LL case. Also try to insert moves earlier and see if that makes finishing off easier.

Ok. Probably. F2L-1 is probably more like 16-18. I think my last one (from round 456) was though. Ok. I'll try that.

Could you possibly do an example of that please? I'm not 100% sure if I understand.

 

[solvelecewbe]

I got this crazy scramble just now. Who can get the best solution?

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

 

[TheNextFeliks]

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

R2 (inserted) D B D' L2 F2
U L2 U' D L' D'
L F U2 F'
U2 L U2 L' U'

How to continue this? 24 moves for f2l-1 with edges oriented.

 

[okayama]

I just submitted my solution for linear solve to fmc.mustcube.net, and I noticed that
the site (checksolution.php) returned the result in a different way from the last week's one.
I already noticed that the last week's one was also a bit different from the previous one
in the way to display password, but this week's one is much different.

Someone seems to make a change in checksolution.php, but I'm not sure who does, hopefully Per.

 

[TeddyKGB]

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

Solution: U' R2 U L' U' R2 U B2 L D' L U' R2 U2 F2 B' R B2 U2 R' F R F' L U L' U2 L U2 R' U L' U' R U2 (35)


Pseudo 2x2x2: * L' B2 L D' L (5/5)

2x2x3: U' R2 U2 F2 (4/9)

F2L-1: B' R B2 U2 R' F R F' (8/17)

Last pair + edges: L U L' U2 L U' L' @ U2 (8/25)

Insert at *: U' R2 U L' U' R2 U L (8/33)

Insert at @: L U' R' U L' U' R U (8/41)

six moves canceling was awesome!!!

This was only my third attempt at FMC i'm pretty happy with the results but I wouldn't mind some pointers

 

[MarcelP]

I am busy writing an optimal insertion finder. To create a list of edge commutator I came up with these

U2 R L' B2 R' L
U2 R' L F2 R L'
U2 L R' F2 L' R
U2 L' R B2 L R'
L R' F2 L' R U2
L' R B2 L R' U2
R L' B2 R' L U2
R' L F2 R L' U2

And after rotating these at all faces I came up with a list of 96 commutators. Are there any (true 8 move) edge commutator that I missed now?

Spoiler

1 : B2 D U' L2 D' U
2 : B2 L R' U2 L' R
3 : B2 R L' D2 R' L
4 : B2 U D' R2 U' D
5 : D2 B F' R2 B' F
6 : D2 F B' L2 F' B
7 : D2 L R' B2 L' R
8 : D2 R L' F2 R' L
9 : F2 D U' R2 D' U
10 : F2 L R' D2 L' R
11 : F2 R L' U2 R' L
12 : F2 U D' L2 U' D
13 : L2 B F' D2 B' F
14 : L2 D U' F2 D' U
15 : L2 F B' U2 F' B
16 : L2 U D' B2 U' D
17 : R2 B F' U2 B' F
18 : R2 D U' B2 D' U
19 : R2 F B' D2 F' B
20 : R2 U D' F2 U' D
21 : U2 B F' L2 B' F
22 : U2 F B' R2 F' B
23 : U2 L R' F2 L' R
24 : U2 R L' B2 R' L
25 : B2 D' U R2 D U'
26 : B2 L' R D2 L R'
27 : B2 R' L U2 R L'
28 : B2 U' D L2 U D'
29 : D2 B' F L2 B F'
30 : D2 F' B R2 F B'
31 : D2 L' R F2 L R'
32 : D2 R' L B2 R L'
33 : F2 D' U L2 D U'
34 : F2 L' R U2 L R'
35 : F2 R' L D2 R L'
36 : F2 U' D R2 U D'
37 : L2 B' F U2 B F'
38 : L2 D' U B2 D U'
39 : L2 F' B D2 F B'
40 : L2 U' D F2 U D'
41 : R2 B' F D2 B F'
42 : R2 D' U F2 D U'
43 : R2 F' B U2 F B'
44 : R2 U' D B2 U D'
45 : U2 B' F R2 B F'
46 : U2 F' B L2 F B'
47 : U2 L' R B2 L R'
48 : U2 R' L F2 R L'
49 : B F' D2 B' F L2
50 : B F' L2 B' F U2
51 : B F' R2 B' F D2
52 : B F' U2 B' F R2
53 : D U' B2 D' U R2
54 : D U' F2 D' U L2
55 : D U' L2 D' U B2
56 : D U' R2 D' U F2
57 : F B' D2 F' B R2
58 : F B' L2 F' B D2
59 : F B' R2 F' B U2
60 : F B' U2 F' B L2
61 : L R' B2 L' R D2
62 : L R' D2 L' R F2
63 : L R' F2 L' R U2
64 : L R' U2 L' R B2
65 : R L' B2 R' L U2
66 : R L' D2 R' L B2
67 : R L' F2 R' L D2
68 : R L' U2 R' L F2
69 : U D' B2 U' D L2
70 : U D' F2 U' D R2
71 : U D' L2 U' D F2
72 : U D' R2 U' D B2
73 : B' F D2 B F' R2
74 : B' F L2 B F' D2
75 : B' F R2 B F' U2
76 : B' F U2 B F' L2
77 : D' U B2 D U' L2
78 : D' U F2 D U' R2
79 : D' U L2 D U' F2
80 : D' U R2 D U' B2
81 : F' B D2 F B' L2
82 : F' B L2 F B' U2
83 : F' B R2 F B' D2
84 : F' B U2 F B' R2
85 : L' R B2 L R' U2
86 : L' R D2 L R' B2
87 : L' R F2 L R' D2
88 : L' R U2 L R' F2
89 : R' L B2 R L' D2
90 : R' L D2 R L' F2
91 : R' L F2 R L' U2
92 : R' L U2 R L' B2
93 : U' D B2 U D' R2
94 : U' D F2 U D' L2
95 : U' D L2 U D' B2
96 : U' D R2 U D' F2

 

[Sebastien]

Interesting! What do you dislike at the one we have?

 

[MarcelP]

Interesting! What do you dislike at the one we have?

It does not find the optimal solution each time.

 

[Cubenovice]

It does not find the optimal solution each time.

interesting...
Do you have an example where IF missed the optimal inertion?

Or do you mean "optimal" as
6 moves for edges
8 moves for corners

Especially for edges there are often no 6 move insertions so you have to use longer commutators.
For corners most of the time there are several 8 movers to be found but ocassionaly there are none.

Tomoaki has posted several examples of the latter.

Are there any (true 8 move) edge commutator that I missed now?

Ehm... you have not posted a single true 8 mover

 

[MarcelP]

interesting...
Do you have an example where IF missed the optimal inertion?

No, not here at the spot, but I will have them as my program is finished.

Or do you mean "optimal" as
6 moves for edges
8 moves for corners

I mean that in total the solution will have less moves because my program will find the optimal solution.

Ehm... you have not posted a single true 8 mover

Oops, I ment 6 ofcourse

 

[kinch2002]

Are you going to check random edge algs that are 7/8 moves as well? There are certainly some 8 moves that could produce shorter solutions than the 6 movers

 

[MarcelP]

Are you going to check random edge algs that are 7/8 moves as well? There are certainly some 8 moves that could produce shorter solutions than the 6 movers

Yes, I intend to do that aswell. I am still only in the first fase of the project. So far I can only find optimal 3 corner inserts. Baby steps forward..

 

[cuBerBruce]

I mean that in total the solution will have less moves because my program will find the optimal solution.

In theory, any skeleton can be converted to an optimal solution for the scramble if you're willing to try long enough insertions. In practice, you need to limit the length or number of algs that you consider as possible insertion algs, and so how "optimal" you're insertion finder will be will depend on how far you're willing to go in the number of insertion algs you consider.

And by the way, I've contrived some tricky cases where I thought the existing Insertion Finder might miss the solution I expected due to needing a suboptimal 3-cycle (for instance), but it would still find it. So if you want to have it find solutions that the existing one misses, you probably have to consider a lot of suboptimal insertion algs.

 

[MarcelP]

So if you want to have it find solutions that the existing one misses, you probably have to consider a lot of suboptimal insertion algs.

Okay, I will keep that in mind. Thanks.