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developing center-safe CLL/ELL for 3x3 shape mods

kadabrium

Member
Joined
Jun 13, 2019
Messages
59
I realized not too long ago that on many 3x3 shape mods CLL/ELL would be easier to recognize than OLL/PLL, and that this might be true also even for their 3-look breakdowns ie. CO/CP/E vs. any bracketing of EO/CO/CP/EP.

Existing CLL algs dont generally present much issue for this method, but ELL for regular 3x3 are usually not center-preserving, and can also involve many M moves which are difficult on shape mods. I have simplistically attempted to compute center-safe ELL algs with cubeexplorer, but the resulting algs arent exactly execution viable.

in the order they appear on algdb with their dubious naming sic'd

F’ U’ F2 D R U R’ D’ U’ F2 U2 F U’
U2 M' U' M U' F2 U2 M' U M U F2 (12s*)2-adj flip

U2 R2 F' U D' L' F2 U2 F2 L U' D F R2 (14f*) 2-flip

U2 R U2 R' U F' U2 F R U' R' F' U L' U L F (17f) 4-flip
U R U R' U2 L U R' U' F U R F' U' L' (15f) 4-flip h
F' R U2 R' L' U F2 L2 F L2 F L U F U2 (15f)
F L' U2 R L U' F2 R2 F' R2 F' R' U' F' U2 (15f)


R L U2 R L' F2 L F R' U2 R L' F2 R F' R (16f) 4 flip z
U R U R' U2 F' L' B' R' U2 R U' B L F U' (16f) bf-flip ua
U2 F' L' F U2 B2 U2 B2 U B2 U F' B2 L F (15f)
bf flip ub
R' L U R U R L' B' R' D2 F2 U2 F2 D2 B (15f)bl-flip ua
U D2 R' U' L' F' U F R L U2 D2 L' U L (15f) bl-flip ub
F R U R' F' U F U2 F' L' U' B' U B L (15f) br-flip ua
R' U2 R U' B L F R U2 R' F' U2 L' U' B' (15f)br-flip ub
R2 F R U R U' R2 F' R U R U R' U2 R (15f)fb-flip h
R U' R' F' U2 F U2 R U2 R' F' U' F (13f*)fb-flip z
U2 R U2 R' F' U' F R U' R' F' U2 F (13f) fr-flip h
R' U L F R' F' R2 L2 B L U' L' B' L (14f*) lb-flip z
U' R U R' U' R' L F R F' L' U (12f)lf-flip ua
F' R U2 D2 L' U2 L U2 D2 R' U2 F (12f) lf-flip ub
F R U R' U' F2 L' U' L U F lf-flip z
F' U F R U2 R' U2 F' U2 F R U R' (13f*)lr-flip z
F' U2 R U2 D2 L' U2 L U2 D2 R' F (12f)
rf-flip ua
U L' U' L U R' L F' L' F R U' (12f)rf-flip ub
U R' F' L F R L' U' L' U L U' (12f) rl-flip ua

U2 F R U R' F' L' U2 L F U' F' (12f)rl-flip ub

A possible compromise i considered is to only orient 3 E-slice centers during f2l, use LL algs that may rotate the last center (presumably R), then finally 1 alg to fix U and R centers. I am however not sure at all how much difference a constraint of 1 center would make on LL (cubexplorer surely didnt find that much better ones), plus i have been unable to find even good algs to rotate said last center pair.
 

SenorJuan

Member
Joined
Sep 26, 2014
Messages
409
Location
U.K
I'm just an amateur when it comes to shape-mod cubes and super-cubes, but you're correct about M-slice algs. They really can ruin a solve if you're unaware.
My strategy for the last layer is to solve edges then corners, formally EPLL then L4C. The EPLL step is easy, and only about 15 algs, several of which are short and simple. The L4C stage is much harder, and two-stepping it is not an unreasonable thing to do. Knowing all 18 3-corner cycle algs is worthwhile.
I find this works OK on mirror-blocks, too.
 

kadabrium

Member
Joined
Jun 13, 2019
Messages
59
I'm just an amateur when it comes to shape-mod cubes and super-cubes, but you're correct about M-slice algs. They really can ruin a solve if you're unaware.
My strategy for the last layer is to solve edges then corners, formally EPLL then L4C. The EPLL step is easy, and only about 15 algs, several of which are short and simple. The L4C stage is much harder, and two-stepping it is not an unreasonable thing to do. Knowing all 18 3-corner cycle algs is worthwhile.
I find this works OK on mirror-blocks, too.
that might be a good idea actually, since ELL are more gen-demanding than CLL so doing that first with less constraints should lead to better algs. is any such alg set already available for regular 3x3? as I don't know how to generate non-last step algs in cubexplorer.
 

kadabrium

Member
Joined
Jun 13, 2019
Messages
59
seems the l4c algs arent much better than my ell. guess thats just what you have to deal with when the pieces you want to solve are scattered wide around. the E algs are marginally better than standard cll algs (but why are a bunch of them listed FB-mirrored?) but EC also has more algs in total than CE. I'm fine with just not having B moves in my algs really.
 

SenorJuan

Member
Joined
Sep 26, 2014
Messages
409
Location
U.K
I agree, it's not the best resource, you do need to have a fiddle with some of the algs, many of the E algs have mirrors /inverses that are equivalent, they're just not listed.
As it mentions in the L4C page, if you know all 18 3-cycle corner commutator algs, you can combine them to deal with the awkward corner cases, like "one corner in place, but incorrectly oriented, the other 3 corners needing a cycle to complete". While it doesn't seem elegant, the typical result seems to be 8-move alg + 9-move alg, not a lot worse than the 15/16 moves of many of the 'proper' algs.

Those cases can also be dealt with by solving the 3 incorrectly-positioned corners so that 2 are solved, then that leaves two corners to orient, a simple but not particularly short alg.
 

kadabrium

Member
Joined
Jun 13, 2019
Messages
59
found this simple pure 4flip M' U M' U M' U M2 U' M' U' M' U' M' (13s*)

Another issue i didnt consider before with shape mods is their added difficulty to finger trick. in its extreme case this may ultimately lead to movecount optimal algs being preferred over ones optimized for regular 3x3 execution. (S and E slices are probably still too slow)
 

SenorJuan

Member
Joined
Sep 26, 2014
Messages
409
Location
U.K
You're more dextrous than me ( not hard ) if you can fingertrick a Ghost cube. I prefer to keep the solve simple, and things that cause trouble, like slice turns and tough-to-recognise situations, I avoid.
I'm sure there are some super-cube safe algorithms listed on this forum, as well as algs specifically to sort out centres on an otherwise solved puzzle. Have a search... I'll try and find then tomorrow if I get time.
 
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