Last 2 edge groups on 7x7

[pjk]

I'm curious how you all are solving the last 2 edge groups on the 7x7. I often find myself in situations where I can't figure out an efficient way to solve it, so I end up using a solve edge group to solve the remaining 2 edge groups.

Are there any specific things you do to make them go quicker? An example of the remaining 2 edges being solved would be greatly appreciated. Thanks

 

[Leviticus]

I solve th first 8, 1 at a time, storing them in the U and D layers, restore centers, turn the last 4 edges into 5x5 edges by making the 3 inner edges a group. So basically 5x5 edges in 5x5 edges.

 

[Mike Hughey]

This probably isn't helpful at all, but I've just been doing AVG edges, first inner, then outer, and there's no difference whatsoever between doing that on 7x7x7 versus 5x5x5. (Except that there are twice as many to do.) (pjk, I thought I remembered you doing AVG edges, but this sounds like you're doing the bigcubes.com method - is that right?)

I have noticed that when I'm doing them this way, the outer edges go MUCH faster than the inner ones. I guess because the center pieces are much easier to see once they look bigger because of the extra pieces paired up with them. If I could get as fast on the inner ones as the outer ones, I think I'd be pretty fast at edges.

 

[DavidWoner]

i do 7x7 edges by reduction(reduced to edges like on a 5x5), but i do not always reduce all edges before i solve them. however, to prevent what you are talking about, i just watch what im doing as i start to get down to the end, and carefully choose which ones to solve in order to prevent any weird cases. i know its a little vague, but basically just pay attention to all edges at once. although i do 2 at a time pairing which might make it easier.

EDIT: wow 2 people posted ahead of me in the time that i wrote this.

 

[pjk]

Leviticus: Yeah, I do the same. The last 2 edge groups is what is giving me trouble. I solve them, but quite slow in comparison to the others.

Mike: Cool. Yeah, for cubes > 5x5, I've been using bigcubes method. For 5x5, AvG is like doing 4x4 pairing but double (24 instead of 12). For anything greater than that, I don't think it is too efficient. I may try using AvG for the remaining 4 edge groups though, that is an idea.

Vault: Okay, cool, that is an idea.

Thanks.

 

[Mike Hughey]

AVG should be the same for larger cubes as it is for 5x5x5. The method is basically identical, except double. So does that mean there's optimization with bigger cubes with the bigcubes.com method? (I'd assume that's the only reason you'd think AVG is not as efficient for bigger cubes - the bigcubes.com method must get better with bigger cubes.) Are you able to do the entire edge at one time or something (instead of just the inner ones, then the outer ones, or something like that)? I guess if you can do that, it becomes more efficient as the cubes get bigger - is that the idea? But I would think that could get rather difficult.

 

[pjk]

AVG should be the same for larger cubes as it is for 5x5x5. The method is basically identical, except double. So does that mean there's optimization with bigger cubes with the bigcubes.com method? (I'd assume that's the only reason you'd think AVG is not as efficient for bigger cubes - the bigcubes.com method must get better with bigger cubes.) Are you able to do the entire edge at one time or something (instead of just the inner ones, then the outer ones, or something like that)? I guess if you can do that, it becomes more efficient as the cubes get bigger - is that the idea? But I would think that could get rather difficult.

Bigcubes method is where I solve the first 8 edge groups, 1 at a time, slicing centers but not rotating them. "The method is basically identical, except double." The except double is the difference to me, everytime the cube gets bigger, it doubles. So 4x4 with AvG is 12, 5x5 is 24, etc. I think after 24, the bigcubes method is much more efficient.

 

[Pedro]

I'm doing the whole "edge" at once on the 7x7
when I get to the last 4, I just do inner, than outer...I don't think there are efficient ways to solve the whole groups with all those weird cases...

for the 6x6, I'm still in doubt about going 4x4-5x5 or whole group at once...

 

[Mike Hughey]

I tried the bigcubes method with both 6x6x6 and 7x7x7, and I guess I can see where it could be pretty efficient. Unfortunately, I'm no longer any good at the method, so it's hard for me to tell how well it would actually work. If you had a case where all of the edges were perfectly divided on a 7x7x7 (each edge has 5 different color pair pieces on it), you wouldn't be able to make a whole edge on a single go, since you'd only be able to get 4 of them on the middle slice. But I guess then you could just do a second try to get the last one in. I did notice that a lot of times on the 7x7x7, you have 2 pieces together (usually even in the proper orientation) on one of the edges before you start, which means you usually can get all 5 at once.

I'd think that as you go up beyond 7x7x7, though, it might get really tricky to do this, since you'd almost always have to take 2 or more passes to get an edge done. You'd have to be careful not to let the confusion slow you down.

Note that with AvG, it's not double every time the cube goes up one - it's just 12 more each time. So 6x6x6 is 36 (like doing a 4x4x4, then a 5x5x5), 7x7x7 is 48 (2 5x5x5s), etc. And the nice thing is that recognition theoretically should never get any more difficult no matter how big the cube gets - all you have to do is look for the middle piece and match to it, so you can ignore all those other cubies. AvG is certainly working pretty well for me so far even on 7x7x7; I have much more trouble with the centers than with the edges.

I wonder what Erik has been using for the bigger cubes? I notice he got rather good times on 6x6x6 in the competition last week (especially considering he had a lot of pops).

 

[pjk]

Note that with AvG, it's not double every time the cube goes up one - it's just 12 more each time. So 6x6x6 is 36 (like doing a 4x4x4, then a 5x5x5), 7x7x7 is 48 (2 5x5x5s), etc. And the nice thing is that recognition theoretically should never get any more difficult no matter how big the cube gets - all you have to do is look for the middle piece and match to it, so you can ignore all those other cubies. AvG is certainly working pretty well for me so far even on 7x7x7; I have much more trouble with the centers than with the edges.

I wonder what Erik has been using for the bigger cubes? I notice he got rather good times on 6x6x6 in the competition last week (especially considering he had a lot of pops).

Ah, yeah, you're correct, my mistake. So far with > 5x5 cubes, I've been liking bigcube method. My edges are pretty quick, my centers just need some work. I will give AvG somemore practice soon though. Thanks for the info.