2GR Method

2017-04-21T19:56:15Z

Teoidus: Created page with "{{Method Infobox |name=2GR |image=2GR.png |proposers=John Li (teoidus) |year=2017 |steps=5 |algs=84 |moves=~49 |purpose= Speedsolving }} 2GR (2 generator reduction) is an..."

{{Method Infobox
|name=2GR
|image=2GR.png
|proposers=John Li (teoidus)
|year=2017
|steps=5
|algs=84
|moves=~49
|purpose= [[Speedsolving]]
}}
2GR (2 generator reduction) is an advanced speedsolving method that reduces the cube to the <R,U> subgroup, allowing for a very ergonomic F2L step and an 84-algorithm 1-look LL.

== Steps ==

1. EOPair: create a 2x1x1 corner-edge pair at DBL-DL while orienting all the edges.

2. CPLine: complete a 3x1x1 line on LD while reducing the remaining 6 corners to <R,U>.

3. Block: expand the line into a 3x2x2 block.

4. F2L: complete the F2L.

5. [https://www.speedsolving.com/wiki/index.php/2GLL 2GLL]: complete the last layer in 1 look.

== Pros ==

* Relatively low move count (comparable to [https://www.speedsolving.com/wiki/index.php/Roux_Method Roux]).

* F2L and 2GLL steps are quite ergonomic, since they are completely 2-gen.

* Very high skip chances (1/324 LL skip, 1/27 COLL skip, 1/20.25 LL completely solvable with a single Sune/Antisune/Backsune/Backantisune).

== Cons ==

* Very steep learning curve: planning EOPair + CPLine is very difficult.

* Lookahead can be difficult during Block if edge pieces aren't tracked during CPLine.

* Movecount largely depends on efficiency during the intuitive stages, so it may be difficult to achieve high tps while maintaining efficiency during those steps.

== Advanced Techniques ==

The following techniques can be used to create more favorable LL cases, or turn bad LS situations into good ones.

* '''Anti-phasing''': A lightweight technique to create much more favorable LL cases. Before F2L is completed, edges are forced to be un[https://www.speedsolving.com/wiki/index.php/Phasing phased], avoiding pure twist 2GLL cases (the longest 2GLLs), Z perms (the longest EPLLs), and increasing chances of solving the last layer with a single Sune variant from 1/20.25 to 1/13.5 (this is twice as likely as an OLL skip in ZZ).

* '''Corner control''': The last pair is solved while forcing a Sune, Antisune, Skip, or H OCLL case (these 2GLL subsets are the shortest), reducing LL movecount.

* '''CO at LS''': If LS corner is already solved, an algorithm can be used to orient LL corners while inserting the last edge; if LS edge is already solved, an algorithm can be used to orient LL corners while inserting the last corner. Both situations leave an EPLL to complete the solve.

== External Links ==

* [http://teoidus.github.io/dump/2GR/2GR.html 2GR Text Tutorial]
* [https://docs.google.com/document/d/1A74Tv5nzoXEzEN1NGORZ8sabOhcFWQmDCMpSpoFTF3I/edit CP Cheat Sheet]
* [https://www.reddit.com/r/Cubers/comments/63y9sy/2gr_method_text_tutorial/ Reddit Proposal Thread]

[[Category:3x3x3 methods]]
[[Category:3x3x3 speedsolving methods]]

File:2GR.png

2017-04-10T03:24:07Z

Teoidus:

Roux method

2017-02-22T15:13:25Z

Teoidus:

{{Method Infobox
|name=Roux
|image=Roux_method.gif
|proposers=[[Gilles Roux]]
|year=2003
|anames
|variants
|steps=4
|algs=9-42
|moves=[[Speedsolving|Speed]]:48, [[FM]]:28-
|purpose=<sup></sup>
* [[Speedsolving]]
* [[Fewest Moves]]
}}

The '''Roux Method''' (French pronunciation: [ʁu]) is a 3x3 speedsolving method invented by [[Gilles Roux]]. Unlike the [[Fridrich]] and [[Petrus]] methods, the inventor of this method has used it to achieve an official sub-15 average. Similarities can be drawn to the Petrus method's block building and the [[Waterman method]]'s layer-on-the-left and edges-last aspects.

==The Steps==

1. Build a 1x2x3 block anywhere on the cube.

2. Build a second 1x2x3 block opposite of the first 1x2x3 block, without disrupting the first 1x2x3 block. After this step, there should be two 1x2x3 blocks: one on the lower left side, and one lower right side, leaving the U slice and M slice free to move.

3. Simultaneously [[orient]] and [[permute]] the remaining 4 corners on the top layer (U-slice). You can use [[CMLL]],[[COLL]], or Corner OLL's (along with the T and Y permutation) to do this.

4a. [[Orient]] the 6 remaining edges using only M and U moves (UF, UB, UL, UR, DF, DB need to be oriented correctly).

4b. Solve the UL and UR edges, preserving edge orientation. After this step, both the left and right side layers should be complete.

4c. Solve the centers and edges in the M slice, ''see [[Last Six Edges]]''.

: ''See also: [[L5E]]''

==Pros==

*Like the Petrus method, the Roux method uses fewer moves than the popular Fridrich method.
*It is also more intuitive and requires fewer algorithms.
*After the first block is built the rest of the cube can be solved mostly with R, r, M and U moves thus eliminating rotations.
*Statistically it is one of the best methods, as shown by [[Alex Lau]]'s success in the WCA.
*CMLL is one of the best algorithm sets as there are only 42 cases and most algorithms are fast OLLCPs from CFOP
*The blockbuilding and intuitive nature of the method allows for rapid improvements in lookahead and inspection
*The LSE step of Roux is very easy to master, as it has easy lookahead and allows for fast, 2-gen MU TPS.

==Cons==

*Block building can be difficult for a beginner to get used to. The reliance on r and M moves may also be difficult for some people, so much so that cubers who have trouble with M turns should probably not use this as their main method (or better, practice practice practice the M moves). Slice turns can also be slower than using a [[quarter-turn metric]].
*Since the M-slice is used often, especially in the final stages, there is a larger chance of a [[DNF]] rather than a [[+2]] if the solver misses the second flick in an M2, or if the solver misses the last M move. It is a DNF because M uses both the R and L face in one.

==Improvement==

Free/non-linear blocks: The first block and second block do not need to be built in that order. You can build part of one and finish the other later. This is very useful when there are a lot of free, pre-built blocks and pairs.

Non-matching centres: The first two blocks can be built around incorrect centres. This allows for more efficiency and allows rouxers to take advantage of pre-built blocks. The centres are corrected directly before CMLL with either u M' u or u' M' u.

Some Roux users have learned multiple algorithms for each CLL case, each affecting edges in a different way. This allows for manipulation of edge orientation, leading to an easier LSE. This is called CMLLEO.

Possibly another improvement is to expand to solving any of the four second blocks. This means that the D-layer colors of the two blocks don't have to match. This is called non-matching blocks. One negative, if someone has already learned a recognition method for CLL, is that to easily use the full range of second block options, a switch to [[NMCLL]] recognition is necessary. Another is that LSE EO is a bit more difficult to recognize in some solves.

Pinkie Pie: a variant proposed by Alex Lau in 2016, it involves orienting the UL/UR edges on the D layer while using an OLLCP algorithm to orient the remaining edges and solving the remaining corners. The user then will get a 4a skip and a very easy 4b step. While this may seem good, many faster Rouxers are of the opinion that it is simply better to influence the EO step and not go to all the hassle of placing UL/UR on D and having to recognise an OLLCP. There is also the reason that many Roux solvers use the method to have less algorithms and do not want to learn the huge OLLCP algset.

EOLR: a variant proposed by Gilles Roux and further documented by Alex Lau, Kian Mansour, and Iuri Grangeiro. It combines steps 4A and 4B of the method, orienting edges and placing ULUR on the D layer simultaneously. The cases are all intuitive, as they involve performing the EO case from different angles to set up a "good arrow" where ULUR can then be placed on bottom.

UFUB: Instead of solving ULUR edges in 4B, UFUB are solved. This can lead to more efficient solutions, but lookahead becomes much more difficult. It is most useful for skipping the "dots" 4C case.

Misoriented centres: Standard roux involves orienting all 6 edges relative to the centre colour that is on the bottom of the blocks. Instead, we can orient them relative to the front colour. As with UFUB, efficiency is improved, but lookahead is hindered. This is most useful for known EOLR cases.

== Notable Users ==
* [[Gilles Roux]] [http://www.worldcubeassociation.org/results/p.php?i=2004ROUX01]
* [[Thom Barlow]] (Kirjava) [http://www.worldcubeassociation.org/results/p.php?i=2006BARL01]
* [[Austin Moore]] (BigGreen) [http://www.worldcubeassociation.org/results/p.php?i=2009MOOR01]
* [[Jules Manalang]] (Waffo) [http://www.worldcubeassociation.org/results/p.php?i=2008MANA02]
* [[Alexander Lau]] (5BLD) [http://www.worldcubeassociation.org/results/p.php?i=2011LAUA01]
* [[Mitsuki Gunji]]
* [[Artur Kristof]] (Arcio) [http://www.worldcubeassociation.org/results/p.php?i=2012KRIS12]
* [[Kian Mansour]] [https://www.worldcubeassociation.org/results/p.php?i=2015MANS03]
* [[Kavin Tangtartharakul]] (GuRoux) [https://www.worldcubeassociation.org/results/p.php?i=2014TANG03]
* [[Vincent Wong]] (Kangaroux) [https://www.worldcubeassociation.org/results/p.php?i=2014WONG08]

==Forum links==
* [https://www.speedsolving.com/forum/showthread.php?3842-Roux-Help-and-Discussion-thread.html Roux help and discussion thread]
* [https://www.speedsolving.com/forum/showthread.php?51553-One-Answer-3x3-Roux-Question.html One-question answer thread]
* [https://www.speedsolving.com/forum/showthread.php?50819-How-to-read-a-Roux-corners-table.html Reading Roux corners tables]
* [https://www.speedsolving.com/forum/showthread.php?47572-Video-Roux-as-a-Beginner-Method.html Beginner's Roux video tutorial]
* [https://www.speedsolving.com/forum/showthread.php?48028-The-Roux-quot-Example-Solve-quot-Game!.html Roux Example solves]
* [https://www.speedsolving.com/forum/showthread.php?35350-Roux-4b-to-4c-Transition.html Roux step 4b-4c transition help]

== External links ==
* [http://grrroux.free.fr/method/Intro.html Gilles Roux's tutorial]
* [https://sites.google.com/view/kianroux Kian's Roux Guide]
* [https://www.youtube.com/channel/UCdEm9-DsuOzNoWmTAYNLRoQ Kian's Youtube Channel]
* [http://wafflelikescubes.webs.com/ Waffle's Roux Site]
* Wikia: [http://rubiks.wikia.com/wiki/Roux_Method Roux Method]
* [http://www.speedsolving.com/forum/showthread.php?t=11506 Waffle's Roux Tutorial]
* [http://rouxtorial.webs.com/ 5BLD's and PandaCuber's Roux Tutorial]
* [http://www.speedsolving.com/forum/showthread.php?29123-The-reconstruction-thread&p=634675&viewfull=1#post634675 Reconstruction for BigGreen's unofficial Ao5 9.51]
* [http://games.groups.yahoo.com/group/speedsolvingrubikscube/message/5923 Original Method Proposal]

[[Category:3x3x3 methods]]
[[Category:3x3x3 speedsolving methods]]
[[Category:Fewest Moves Methods]]

Speedsolving.com Wiki - User contributions [en]

2GR Method

File:2GR.png

Roux method