The Fairness of the +2 penalty

Discuss the WCA regulations.

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Re: The Fairness of the +2 penalty

Postby TMOY » Fri Jan 02, 2009 6:17 pm

anders wrote:As a corners-first guy, I would be happy if a misaliged slice is awarded a penalty instead of dnf. This happens to me occasionally, in particular in OH-solving. On the other hand, I appreciate that we only have one definition of a move in the regulations. Since fewest moves use HTM, it is also approprate to use HTM when discussing the solved state of a cube in speedcubing.

As another corners first guy I think it should be changed for both. A slice move is definitely only one move, counting it as two is ridiculous.
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Re: The Fairness of the +2 penalty

Postby Dene » Sat Jan 03, 2009 8:45 pm

Currently the regulations allow for the face to be 45 degrees off. Are you all claiming that even 0.000000001 degree off is now a DNF? Who is going to judge that? We would need extremely expensive equipment to work that out. What a silly proposal.
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Re: The Fairness of the +2 penalty

Postby Gilles » Sat Jan 03, 2009 8:55 pm

Dene wrote:Are you all claiming that even 0.000000001 degree off is now a DNF?

No.
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Re: The Fairness of the +2 penalty

Postby Dene » Sat Jan 03, 2009 9:10 pm

Oops silly me I missed the point completely. Sorry.
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Re: The Fairness of the +2 penalty

Postby Gilles » Mon Jan 05, 2009 2:26 am

qqwref wrote:Incidentally, I think an M slice off (or r on a big cube) should be +2, not DNF. The reasoning is the same. I think in all situations where a slice move is misaligned, it was executed as one move, so it should be treated as such.


The reasons for "Slice moves counted as 2 moves"

This question has been discussed a lot in the past years and it is a very legitimate question (I personnally "think slice" and often perform such moves physically as one move).
Maybe it is necessary to explain again the reasons why slice moves are counted as 2 moves as if they do not exist.

It is important to know what a move is for different purpose:
1) Solved state and penalties.
- Misalignement threshold of puzzle parts beyond which at least a move is considered.
- Since we got "+2 penalty" for "1 move away from solved state" and "DNF" for "2 moves away or more", it is important to know what falls into the "1 move" category.
2) "Fewest moves".

Using the "Half Turn Metric" ("Half turn"? What a bad name!) is an elegant solution to our problems.

Take any twisty puzzle, it basically is:
- a volume,
- cut planes that make parts of the volume free to move.

This is my vision of twisty puzzles. WCA won't ask you to change your way of considering puzzles, but what's interesting for WCA is:
- it is easier to see when the puzzle is "one move away" from solved state, especially on big cubes, just focus on a cut plane,
- it is generic (same rule for any twisty puzzles, you only need to set specific limits in article 10f),
- it is consistent (same rule for penalties and "fewest moves").

I can understand you don't care about genericity and consistency (by the way, is UD' a slice move even on Megaminx?) because you focus on speed cubing and penalties.
But if you want to count slice moves as 1 move only, I can show you pictures where the cube state is impossible to judge.
Take a 7x7x7 and apply an "E" move that rotates together layers 2-3-4-5-6.
When looking at the resulting cube, if it was a clean move, you can visually say there's only 1 move applied. But penalty cases in such circumstances rarely are that clean. Firstly, you would have to make groups of compatible adjacent layers. Then, decide if there's only a group misaligned between two others that are aligned.
If, on your 7x7x7, layers 2-3-4-5-6 are vaguely aligned, between layers 1-7 very loosely aligned, you can't decide if it's a slice move.
It's easier to see on a 3x3x3 I admit, but I pretend you can only compare correctly two adjacent parallel layers.


------------------------------

No more penalties for misalignments!

Now, we would not be talking about this if the penalty for misalignment did not exist.
In my opinion, this penalty is a mistake and bloat, like the extra attempt for pop rule was. When you don't cleanly finish your solve, you deserve a DNF, just like when you stop the timer with a popped piece.

With puzzles that take long, you can afford a check. On fast puzzles, well, it's part of the dexterity challenge! And if your 2x2x2 get misaligned everytime you drop it on the table, because it's too loose and you put too much lubricant inside, blame yourself.

You may consider it would be a bit crual. I think cubers now are mature enough to accept it.
Rules would be more simple, and easier for judges (Bilbao...).
No more questions like:
- Is it fair to have +2 for all puzzles?
- Why don't you allow slice moves?
- Why is U2 not DNF? It's not just a slight misalignement, the cube is clearly missing a full big move!
- Why is a cube lacking (U/2)R2 (orthogonal slices) only a penalty case?
And no need to define a metric for speed cubing anymore. The only metric is time, because it is speed cubing, not "fewest moves".

I can't read the proposal for getting rid of this +2 penalty in the draft. Could WCA explain why it has been rejected?

Gilles.
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Re: The Fairness of the +2 penalty

Postby blade740 » Mon Jan 05, 2009 6:58 am

I wouldn't mind getting rid of the +2 penalty altogether. The last turn is as much of a turn as every other turn. Sure, a puzzle that is U away is obviously solved, but so is a puzzle that is U D. And, one might argue, one that is U R (if you know how to resolve it, that is). And so on and so forth. Where do you draw the line? 1 move is arbitrary. 0 moves is absolute. I agree that in most cases a slice move is one move, and if the penalty remains I would like to see slice turns included under the +2 category. Still, a more effective penalty is DNF. Set your puzzle down accurately and there's no problem.
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Re: The Fairness of the +2 penalty

Postby Lucas » Mon Jan 05, 2009 8:29 am

blade740 wrote:The last turn is as much of a turn as every other turn.

The regulation is not there to allow sloppiness, it's there to compensate for puzzles misaligning after they have been solved. If you make a wrong turn during a solve, you are holding it, and have a chance to see it and correct it. After you release a cube, it is beyond your control.
At Nationals '08, my only +2 on 2x2x2 as on a solve where I released the cube quite accurately, and it bounced to do an L' turn. It was disappointing, but I had to accept that it was a turn off. A larger penalty might simply be annoying, but that solve was definitely not a "Did Not Finish."
I would be in favor of disallowing a +2 for BLD, considering the accuracy nature of the event. However, for speedsolve, I think it is too big a change to remove the +2 after the first version of the 2009 regulations; there has not been time for discussion under the supposition that it might actually be removed.
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Re: The Fairness of the +2 penalty

Postby qqwref » Mon Jan 05, 2009 8:35 am

Edouard Chambon wrote:It's not that difficult to stop the timer while being sure the cube is solved.

And for BLD, I know some cubers who know that unset up the last move would take more than 2 sec (to remember correctly) so they don't do it and stop the timer, knowing they will get a +2.


But I don't want +2 for people who don't do AUF on purpose, I want +2 for the misalignment. It is of course impossible to get a U2 by just dropping the cube (so maybe it should be qtm, round to the nearest face and if it is more than one quarter move off it is DNF), but getting one layer misaligned is quite possible, and even if you don't think so it is still easy to see how a layer could be more than 45 degrees misaligned. I think it is wrong to give out a DNF on a cube that was very clearly solved when the cuber released it.
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Re: The Fairness of the +2 penalty

Postby Bob » Mon Jan 05, 2009 9:04 am

qqwref wrote:It is of course impossible to get a U2 by just dropping the cube (so maybe it should be qtm, round to the nearest face and if it is more than one quarter move off it is DNF), but getting one layer misaligned is quite possible, and even if you don't think so it is still easy to see how a layer could be more than 45 degrees misaligned.

Perhaps, then, a compromise (and transition to a more strict policy in which misalignments are disqualified?) could be something like the following:

Regulation) More than 45 degrees is +2 (same as 2008), but more than 135 degrees is DNF

It should not be possible (or at least very very unlikely) for the cube to misalign more than 135 degrees when hitting the surface.
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Re: The Fairness of the +2 penalty

Postby TMOY » Mon Jan 05, 2009 9:25 am

Gilles wrote:Take a 7x7x7 and apply an "E" move that rotates together layers 2-3-4-5-6.
When looking at the resulting cube, if it was a clean move, you can visually say there's only 1 move applied. But penalty cases in such circumstances rarely are that clean. Firstly, you would have to make groups of compatible adjacent layers. Then, decide if there's only a group misaligned between two others that are aligned.
If, on your 7x7x7, layers 2-3-4-5-6 are vaguely aligned, between layers 1-7 very loosely aligned, you can't decide if it's a slice move.


Yes it is possible to decide. Count the number of "big slices" on the cube. A big slice is a group of layers where any two adjacent layers are misaligned by less than 45 degrees, and where any layer of the cube adjacent to one of them but outside the big slice is misaligned by more.
Only one big slice: cube solved, OK
Two big slices: cube off by one move, +2.
Three big slices, and the layers of the two extreme ones which are closest to each other misaligned by less than 45 degrees: off by one slice move, +2.
All other cases: DNF.
I don't see any ambiguity in that.
And the UD' slice move on megaminx is a non-problem. I've never seen anybody use such a move, not even people like me which use it intensively on the cube, and dodecahedrons off by UD' do not happen at all.
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Re: The Fairness of the +2 penalty

Postby Gilles » Mon Jan 05, 2009 10:50 am

Bob wrote:More than 45 degrees is +2 (same as 2008), but more than 135 degrees is DNF

It should not be possible (or at least very very unlikely) for the cube to misalign more than 135 degrees when hitting the surface.

90 degrees would be easier. 2xPi/N, with N=3, 4 or 5. (Would forbid the orthogonal slices problem too)

TMOY wrote:Yes it is possible to decide.
...
Three big slices, and the layers of the two extreme ones which are closest to each other misaligned by less than 45 degrees: off by one slice move, +2. (*)
...
And the UD' slice move on megaminx is a non-problem.(**)

I think you didn't get my points. Let's talk next time we meet.

(*) That's the problem, you can't reliably compare distant parts.
(**) You are being too practical. It's not a problem in competitions, but it shows that we can "think slice" with cubes because of the special and convenient nature of cube puzzles. It is not a generic feature.
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Re: The Fairness of the +2 penalty

Postby BryanLogan » Mon Jan 05, 2009 1:57 pm

Lucas wrote:After you release a cube, it is beyond your control.


Well, then you're releasing it wrong.
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Re: The Fairness of the +2 penalty

Postby Lucas » Mon Jan 05, 2009 6:53 pm

BryanLogan wrote:
Lucas wrote:After you release a cube, it is beyond your control.


Well, then you're releasing it wrong.

I would like to see you release a cube "correctly," so that you still have control after you are no longer touching it.

I am in favor of the "45-135" rule or even the "45-90" rule, as it discourages excessive sloppiness while maintaining the idea of practical forgiveness instead of a harsh boundary.
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Re: The Fairness of the +2 penalty

Postby BryanLogan » Mon Jan 05, 2009 7:22 pm

Lucas wrote:I would like to see you release a cube "correctly," so that you still have control after you are no longer touching it.


I do it by placing it on the table, rather than dropping it. If you drop it, you take the risk of DNF. My Square-1 can actually get two turns away from the solved state if I drop it. People would still be allowed to drop it if they want to, but they're taking a risk.
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Re: The Fairness of the +2 penalty

Postby StefanPochmann » Mon Jan 05, 2009 8:13 pm

BryanLogan wrote:I do it by placing it on the table, rather than dropping it.

Yeah, but for the fast people the fraction of a second that this might cost them matters.
We're speedsolvers, not speedreleasers. Ideally we'd measure the solve and nothing else.
The +2 penalty let's us get closer to the ideal.
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Re: The Fairness of the +2 penalty

Postby BryanLogan » Mon Jan 05, 2009 8:23 pm

StefanPochmann wrote:
BryanLogan wrote:I do it by placing it on the table, rather than dropping it.

Yeah, but for the fast people the fraction of a second that this might cost them matters.
We're speedsolvers, not speedreleasers. Ideally we'd measure the solve and nothing else.


Yes, that's ideal, but it's never going to happen. Again, this is about control. Just like having slopping turns could result in a pop (and a bad time), having a sloppy release could return in a turn and a bad time. When the "No extra solve for a pop" went into effect, do you think people tried to hone their turning skills to avoid pops, even though it cost them a fraction of a second? I'm guessing if you didn't have the +2 rule, that people would practice more on their release. But I'm guessing in reality, people will simply continue to drop, and if they get a DNF because of a turn, then simply be cautious on the remain solves.
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Re: The Fairness of the +2 penalty

Postby StefanPochmann » Mon Jan 05, 2009 9:10 pm

BryanLogan wrote:Just like having slopping turns could result in a pop (and a bad time)

Fault of the cuber.

BryanLogan wrote:having a sloppy release could return in a turn and a bad time.

Fault of the procedure.
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Re: The Fairness of the +2 penalty

Postby Bob » Mon Jan 05, 2009 11:20 pm

Gilles wrote:
Bob wrote:More than 45 degrees is +2 (same as 2008), but more than 135 degrees is DNF

It should not be possible (or at least very very unlikely) for the cube to misalign more than 135 degrees when hitting the surface.

90 degrees would be easier. 2xPi/N, with N=3, 4 or 5. (Would forbid the orthogonal slices problem too)

Such as < 90 = Ok, >90 = DNF? (for a cube, here. Of course I am speaking too generally and would apply the same logic to all twisty puzzles)
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Re: The Fairness of the +2 penalty

Postby qqwref » Tue Jan 06, 2009 2:12 am

I still like the 135 degree idea because 90 degrees is too unreliable. Suppose you forget to do AUF and you are exactly a U or a U' off. Then if you are a fraction of a degree away from solved it's DNF, but if you are a fraction of a degree towards solved it's +2? That's silly. We also have to think about the case where it is a U' off and then something like 20 degrees of R. Normally this would be one move off so +2. But it is a "total" of 110 degrees off, so is it a DNF now? It's confusing. But I've never seen an accidental misalignment of significantly over 90 degrees.

One radical proposal might be to check the puzzle when it was last touched by the competitor. This would require the judge to look very carefully, but it would (a) give no penalty for accidental misalignment, since you can visually verify that the puzzle was solved before it hit the table, and (b) give a penalty for people not doing AUF on purpose, since you can tell whether the misalignment was there before it hit the table or not. If cubing goes professional, and we had video replays of all solves, we could check this very easily to give penalties completely fairly (i.e. only when the error is the solver's fault). We could also check for cheating on Magic, but that's another issue completely.

An alternate idea for the future would be to try to modify the equipment itself so that we don't get misalignments. Suppose you had a thick surface similar to a mattress. Even if a puzzle falls on a corner on a surface like that, it probably won't misalign, so maybe that would fix the accidental +2s, and then you could just award DNFs for misalignments of over 45 degrees. Ideally you'd also never have the situation where dropping the cube causes a pop, because the landing would be so soft that the puzzle would not have enough force subjected to it to pop a piece out, even if it was very loose. This idea wouldn't be suitable for magic-type puzzles, but it might help reduce +2 issues for anything where you do your solve in the air.
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Re: The Fairness of the +2 penalty

Postby BryanLogan » Tue Jan 06, 2009 2:28 am

StefanPochmann wrote:
BryanLogan wrote:Just like having slopping turns could result in a pop (and a bad time)

Fault of the cuber.

BryanLogan wrote:having a sloppy release could return in a turn and a bad time.

Fault of the procedure.


Yes, but many sports measure things other then the "main" goal. Swimming is a combination of swimming fast, but also swimming in a straight line, turning around, and jumping off the blocks. I'm guessing the jumping would be similar to the dropping the cube. It's not the main goal of the sport, but it can cause you to DNF if you don't do it properly, and it also can mean the difference of precious time.
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