[Help Thread] Petrus Discussion and Help thread

[JLarsen]

Triple posting but I have a question;

Someone suggested to me recently that doing 2 bad edges at a time is not a good method of approach? I never bothered making sure I was doing 2 flips that cancelled into 4 flips, and I never both recognizing if I have 6 bad edges either. In either case I just immediately find 2, and lookahead for another 2. It's actually kind of rare that in the case of 4 I'll do something like (R U' R') (R' F' R). You only save one or two moves at best? Does anyone here actually recognize 6 bad edges and just place the solved edge and do one of those fancy 6 flips? If so, what do you average?

 

[oll+phase+sync]

Is there a more direct way to solve 4x4 using Petrus? Like Roux has K4 and ZZ has Z4. I have an idea.

On of the strenght of petrus in my opinion is, that you can use your inspection time better compared to doing a cross. ( this also implies why CFOP is great cpmpanion of reduction )

My idea for petrus on a 4x4 would be:

1. plan 3 - 5 edge-pairings during inspection (ony do as much edges as you plannend )
2. centers ( while not destroying edges)
3. build a 2x2x2 (you have the bonus that recognition for the edges you need is even better now than on a 3x3)
4. continue on the 3x2x2 maybe with direct placement of edgepieces ( this could make this step even less fearsom as on a 3x3 )
... now all unsolved piece are scattered around only on 2 faces wich is also nice.

 

[oll+phase+sync]

I've been learning Petrus, and I've been wondering what the average move count for the extension step should be. And what the maximum you'd need is. I think this is my slowest part.

This is also a point I'very interested in, sometimes I even intstantly see all 3 pieces, and have an idea what to do - but than I need 8 or 9 moves for the extension.

 

[JLarsen]

I think mine suck too. CYrus* asked me for a movecount of each step in my speedsolves. Here's a copypasta from my response;

Spoiler

Solve 1

2x2- 6
2x2x3- 11
EO- 7
4a- 7
4b- 8

Solve 2-

2x2-9
2x2x3- 10
EO- 4
4a- 6
4b- 8

Solve 3

2x2- 5 =] that one was good
2x2x3- 2 0_o
EO- 7
4a- 7
4b- 8

Solve 4-

2x2- 5
2x2x3- 8
EO- 8
4a- 5
4b- 8

Solve 5

2x2- 8
2x2x3- 12
EO- 6
4a- 6
4b- 11

Interesting. My 2x2x3 seems pretty lengthy too. 2x2x3 is a ***** of a step.

Seems to be about an average of 10 moves.

 

[Cyrus C.]

You sure that was Cride that you sent it to?

I just did an average of 12 for my 2x2x3 extension move counts, it was 7.42. I wonder how this compares to the time it takes me to actually do the extension in a solve though?

EDIT: I just did an Avg of 12 for my 2x2x3 extension. It was 3.28. That time includes inspection.

 

[JLarsen]

Lol both of your names start with a C and you both do Petrus/blockbuilding stuff. I just did speedsolves and reconstructed. Or I just counted and turned as fast as I could without losing count of the moves while not trying too hard to look ahead. Not crazy accurate but it's better than doing slow solves and inspecting 2x2x3 ahead of time.

 

[oll+phase+sync]

Triple posting but I have a question;

Someone suggested to me recently that doing 2 bad edges at a time is not a good method of approach? I never bothered making sure I was doing 2 flips that cancelled into 4 flips, and I never both recognizing if I have 6 bad edges either. In either case I just immediately find 2, and lookahead for another 2. It's actually kind of rare that in the case of 4 I'll do something like (R U' R') (R' F' R). You only save one or two moves at best? Does anyone here actually recognize 6 bad edges and just place the solved edge and do one of those fancy 6 flips? If so, what do you average?

What helped me in the 4 bad case was to look for two bad edges in the R or L face- these are the candidates for an R2/L2 third move.

For 6 bad edges i do M'UM L'U'L (the bad is RF) or an mirror.

What is also of big help to see patters fast is the fact, that orientation rules always apply to the opposite color, too (think this info is not new) eg. the the top face is Yellow, the alll rule for an Yelleow sticker will apply to the white sticker to.

 

[JLarsen]

I probably should have had this conversation here to begin with, but I thought it was a good one.

An idea I had;

Within the confines of speedsolves, do you think there is a correlation between efficiency of solves and standard deviation?

I'll try to word this the best I can....

Consider two solving styles.

1. Slow turning and efficient
2. Fast turning and inefficient or brute force

My thought process is that that 1st solver will be more inconsistent because the speed of their solve is more reliant on the luckiness of the solution, (or efficiency), and is more affected by longer solutions. The second solver I would think would have a much more stable move count, and be less effected by bad cases because they are more brute force oriented to begin with. The logic is kind of after the fact in that I'm using more efficient solutions recently, but I'm getting really bad singles mixed in with incredibly fast singles. Thoughts?

PS

Please tell me how well I'm explaining things or ask me to clarify if my wording is bad. I feel like I explain things poorly too often so I took more time than normal to write this post. I've been doing the same on my other posts as well.

Slower turners will always be most affected by the luckiness of the solves, due to the nature of slow turning. (This assumes by Slow/Fast you mean TPS (look-ahead considered)) I think the standard deviation of the solve times is affected by the standard deviation of the efficiency of the solve. i.e. if Method Q has an average move count of 45, but solves are generally between 30 and 60 because there is a high chance of skips, the solver's SD will be high (relative to their average) regardless of turn speed. If Method V has an average move count of 60, but solves are generally around 50 due to skips being very hard to get, the SD of the solver will be low. This also assumes that the sub steps of both methods have consistent move count. If, for example, 12 of your PLL algs are 15 moves and 8 are 30 moves, then your SD would be higher.

Does that make sense, or am I misunderstanding your post?

Thanks for responding to my post! You definitely understood exactly what I was saying. Given what you said about Method X vs Method Y in terms of how much it skips, do you think that Petrus would have a higher SD on average than Fridrich? (I suppose *would solvers* have a higher SD) I don't have an incredible amount of experience with Fridrich but it seems like Petrus has a lot more room to skip massive amounts of a solve. I posted something like a 30 move speedsolve I got the other day and I got something around a mid 30 today as well. Do you have much experience with Fridrich? If so do you feel like lucky solves are more possible with other methods?

 

[Erzz]

I actually think SD would be dependent on the cuber's solving style. If the cuber tried to skip parts of the solve (Multislotting, XCross, Winter Variation for some Fridrich examples), then their SD would be higher depending on how much they can skip each individual solve. If the cuber tried to just straight solve the cube without trying to skip things, their skips would be much more rare, and therefore their SD would be lower. Maybe.
Unfortunately I never really got into Petrus that much, maybe someone else can comment on that.

 

[mariano.aquino]

I´m the fastest petrus user of my country... and maybe the only one! hahah. i´m pretty slow yet, avg 28, single 18. just by looking at that, u can see that my deviation is huge!
i´m learning COLL, and it´s true, sometimes i get a pll skip, and sometimes i get a Z...
also sometimes the EO is done, so i can easily blockbuild last step of f2l without much addition in your nmbers but u can also have bad 6 edges and that counts as well..

 

[JLarsen]

Nice dude. I wish I could say that. Gogo sub 20.

 

[mariano.aquino]

i wish there would be more petrus users here..! i´m the only black sheep of the group, hehe
i´try to upload some videos, there´s not enough petrus on youtube!

 

[Tiersy]

Yeah it would be nice+useful to have loads of Petrus solvers to exchange ideas and tips, never mind though... maybe one day! Until then we gotta stick together
I realised after browsing the forum that I have never really practised (as weird as that sound) should probably get my ass in gear and get quicker.

I tried out some of the BB examples posted on the first few pages of this thread and damn some people are efficient!

I think my optimal solve with no faffing would probably be like sub-25, if i learn COLL and get my ass in gear maybe I could bust out some sub-20 solves, damn I would be proud of that!

Power to the Petrus!

 

[mariano.aquino]

Wow, we have almost the same numbers!
however, i range between 20 and 40, i´ve learnt 20/40 COLLs and i´ve gotten a few sub20s =)
i´m also learning roux, that also abuses from COLLs, and i´ve got a 33.4 avg5 and a pb of 28.5. wish i could be as fast as i´m with petrus!
and, hell, yeah, there some BB monsters in here..!

 

[mljonesqwe]

Does anyone have any tips or know of a good video for the 2x2x3 expansion? This is by far my achilles heel. I look ahead and do great on the 2x2x2, and then fall victim to fridrich brainwashing (lol) and put the matching edge down and solve the slot. I know this isn't efficient at all, and want to break the habbit. Any ideas?

 

[OMGitsSolved]

Does anyone have any tips or know of a good video for the 2x2x3 expansion? This is by far my achilles heel. I look ahead and do great on the 2x2x2, and then fall victim to fridrich brainwashing (lol) and put the matching edge down and solve the slot. I know this isn't efficient at all, and want to break the habbit. Any ideas?

Watch Erik Johnson's vids. They are amazing. His name on YT is CaptainCrash55, I think. Just search "captain crash petrus" or "erik johnson petrus"

EDIT: Ugh, still avging 20-23.

 

[JLarsen]

It's actually "Captiancrash44" -yes it's spelled wrong. I honestly don't think you're going to get sub 20 until you devote yourself to the method.

 

[mljonesqwe]

Lol, I wish I had a 20 average. I have to start practicing more. I switched to petrus 2 months ago or so (that rhymed ) and just need to dedicate myself to getting better. Petrus has been great for my average though, taking me into the 30's.

 

[JLarsen]

The hard part is sub 20.....so many months...

 

[rcbeyer]

The hard part is sub 20.....so many months...

this is a very true post. . .
gah, i've used Petrus as my main f2l method for a long long time and i've only had 1 sub 20 avg of 5. . . i routinely get 16-18 solves, but to average is soooo hard sometimes. . . my last avg of 5 was 20.xx and avg of 12 was 21.xx

definitely takes time however Practice always prevails lol