二阶高级方法之SS法 [复制链接]

jacksj

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电梯直达

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发表于 2009-8-20 16:37:06 |只看该作者 |正序浏览

这个方法找得我很辛苦，整个Internet相关帖子不超过3个，这要多谢2rabbits的热心帮助，现在我拿出来给大家分享。
SS法全称叫是SunStern
這個解法分為3個步驟

step 1. 3/4面

step 2. 完成剩下的1/4面, 同時完成OLL

step 3. PBL

PBL公式量少, 步數少

除了CLL和EG系統外, 大部分的2x2x2解法都是在PBL之前的部分下功夫

(eg. Ortega, Guimond, OFOTA, SS, G-FASSST)

公式方面

step 1: 0 (intuitive)

step 2: 103 (扣掉鏡射後為55)

step 3: 5

說明

3/4面完成┬──>最後1/4在底層┬──>0度───>7 algs (這條就是所謂的Ortega)
      │                │
      │                │
      │                ├──>+120度───>8 algs ─┐
      │                │                         ├(Guimond的16種
      │                │                         │ cases)
      │                └──>-120度───>8 algs ─┘
      │
      │
      │
      │
      │                   (底層最後一角)
      └──>最後1/4在頂層┬──>0度───>7x4-2=26 algs
                           │                      ╴╴
                           │             (-2是因為 □□ )
                           │                            □□
                           │                            ￣￣
                           │
                           │
                           ├──>+120度───>8x4-2-3=27 algs
                           │                         ╴       ╴
                           │             (-2是因為 ■□ -3是因為 □□︳)
                           │                            □■             |□□
                           │                            ￣                ￣
                           │
                           │
                           │
                           └──>-120度───>8x4-2-3=27 algs
                                                      ╴             ╴
                                             (-2是因為 □■ -3是因為 |□□ )
                                                      ■□          □□︳
                                                         ￣          ￣
以上摘自：http://6yo.org/f/viewtopic.php?f=8&;t=24866&p=72324

SS_0_1.pdf (23.39 KB, 下载次数: 584)

关于SS的起源和步骤
Stern-Sun Method

Introduction
Note: There has been some controversy over the naming conventions. ErikAkkersdijk has objected to the name "SS" because it excludes anyauthorship he had with the method and its World War II connotations.Unfortunately, we could not convince the public enough to refer to themethod as "LP" or any other name, so it seems "Stern-Sun" sticks.

In August 2007, I started learning the Guimond method and startedaveraging 5-6 seconds with the method (check out my results at theGuangdong Open 2007 and Beijing Open 2007). At some point I decidedthat a bit of optimization would be useful. For those not familiar withthe Guimond method, the first (or some call "zeroth") step involvescreating 3/4 of a face of opposite colors (in the standard BOY colorscheme, white-yellow, for example). My optimization considered eightcases that fell under what would become a subset of Stern-Sun. Thiscase involved 3/4 of a face and the fourth piece on the same layer butoriented incorrectly. I generated some algorithms for those cases, butnever learned them.

Some time in Fall 2007, Mitchell Stern posted on TwistyPuzzles sayingthat he had a "secret" 2x2x2 method as some sort of optimization forOrtega (told to him by Erik Akkersdijk, but for historical and namingreasons (ASS method?), we leave his name out). Here is the exactmessage as communicated over MSN:

"1) get 3 colors of a face (not layer), and make sure that the last piece for the face isn't on the same layer (1-2 moves)"

I looked and that and thought the only missing part is my ownoptimization (and of course the trivial easy faces for Ortega method).After deciding that we'll learn this in the future, we had split offfrom there in style of generating algorithms.

Mitchell used Ksolve and I used Ron's MiniCube Applet to generatealgorithms. For him, cases were categorized through the orientation ofthe fourth piece. As seen on my site, I divided them by the orientationof the 2nd face as a whole. In my opinion, this is a superior methodfor categorization, as recognition only requires one "look." Mitchellgot lazy (schoolwork, I mean) and never learned the method untilrecently (Summer '08) while I went ahead and learned it over the spanof four months (I suppose it's possible to learn in under a month).
Step 1: 3/4 Face

The trivial part. I believe this step takes 0-2 moves, and about 1 moveon average. If you want to be fast, you need to be able to see ahead tothe next step and perhaps even part of Step 3. Unlike Guimond, don'tworry about the 4th corner's orientation: all the cases are accountedfor in the next step. According to Bruce Norskog, this step actuallyranges from 0-3 moves and averages 0.8 moves. Thanks Bruce!
Step 2: Last Piece + Orientation

The daunting part. The algorithms aren't nearly as long as LucasGarron's CLS algorithms. This step's algorithms are surprisingly shortand/or fast and range from 3-7 moves. Some are two-generator, meaningthey only use two faces. These "2-gen" algs are usually the fastest.Note that in the page with all the algorithms, the fourth corner is atthe DLF slot, and there are no symmetry algorithms listed. If I didn'tlearn separate algorithms, you don't need to, either.

List of Algorithms
Step 3: Permute by Layer

This is a dumb step you can read all about on pages detailing the Guimond or Ortega method. Go find them yourself.

In August 2007, I started learning the Guimond method and startedaveraging 5-6 seconds with the method (check out my results at theGuangdong Open 2007 and Beijing Open 2007). At some point I decidedthat a bit of optimization would be useful. For those not familiar withthe Guimond method, the first (or some call "zeroth") step involvescreating 3/4 of a face of opposite colors (in the standard BOY colorscheme, white-yellow, for example). My optimization considered eightcases that fell under what would become a subset of Stern-Sun. Thiscase involved 3/4 of a face and the fourth piece on the same layer butoriented incorrectly. I generated some algorithms for those cases, butnever learned them.

-----多谢2rabbits
更多资料请见
http://www.chilerubik.com/wp-content/uploads/2008/12/stern-sun.pdf
注：版权归Stern、Sun所有 Sebastian Pino Castillo Stern整理

[ 本帖最后由 jacksj 于 2009-8-20 20:27 编辑 ]