Meme: LJ MindMap
Tuesday, March 23rd, 2004 04:28 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
(I'm not sure I quite get this. Okay, it looks pretty and vaguely interesting, but what does it mean? I already looked this and this over, and don't feel particularly enlightened.)


MindMap
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MindMap
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Date: Tuesday, March 23rd, 2004 01:32 pm (UTC)no subject
Date: Tuesday, March 23rd, 2004 03:05 pm (UTC)So, not only do you have mutual links with obra, and jbsegal, and exponentialdk, and onetwolittleb, avacon, oonh, tcb, crs, and chrysaphi... they also all have mutual links with each other. Which when you think about it, really is a neat little bit of information to extract. Then the next tier is cthulhia, rjpb, and tenore, who have mutual links with you and most but not all of your "core" tier. And so on.
Apparently I don't share enough mutually interwoven links to even appear on your mindmap, which is sort of odd considering how much of our friends lists we share. But it doesn't so much measure that as those networks in which everyone has everyone else friended. I only appear on the fringes of my own!
I thought it was cool enough that I made a donation and asked for a color one.
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Date: Tuesday, March 23rd, 2004 05:07 pm (UTC)no subject
Date: Tuesday, March 23rd, 2004 05:21 pm (UTC)No, I Take That Back
Date: Tuesday, March 23rd, 2004 05:23 pm (UTC)no subject
Date: Tuesday, March 23rd, 2004 09:53 pm (UTC)He then takes this information and applies size, color, and location to indicate the groups. As far as I could find, he hasn't specified how he sets each characteristic, but it appears that closer and larger names are more connected to you than smaller and farther names.
The calculations to generate the map are very computationally intensive and become moreso as the number of Friends you have increases, to the extent that sufficiently large numbers of Friends can break the system. This may mean that Friends of yours who in turn have a high number of Friends may not appear correctly on your map. (Since
The two useful pieces of data you can get from the map are that people who are close to you have a large number of Friends in common with you and Friends who are clustered on your map are likely to share each other as Friends. Without a more concrete explanation of the significance of size and color, it's difficult to say more.
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Date: Tuesday, March 23rd, 2004 11:18 pm (UTC)The big names in the middle are not just closely linked to the "seed" (the name in the center), but to Each Other as well. That's the Secret Sauce of the LJMindMap.
The computational complexity
Size and shade define the first three tiers. In black and white, anyway, the big font bright is tier One, big font dimmer is tier Two, and littler font is tier Three. Beyond that is past three. So if tier One has seven-way friendships, these people are in big and bright. Then probably a six-way or two occupy the same size, just dimmer. Color defeats this dimmer-brighter thing, but it's a tradeoff to get the beautiful colors.
The intrigue derives from the cross-germination of many subtle hints and details. Alone they're just mush.
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Date: Wednesday, March 24th, 2004 02:21 pm (UTC)Start with your Friends list. Only include people who have also Friended you. In my case, I had 28 names, starting with:
avon
blkdrgn
chanaleh
cmouse
cnoocy
For each person on your Friends list, go to their info page and look at their list of Friends. For each of your Friends which shows up on that person's list, write down that pair of names. Here's the catch. Both people have to list the other person as a Friend, so the person has to appear in both the Friends list and the Friends Of list. I had 113 pairs, starting with:
avon cnoocy
avon colorwheel
avon cthulhia
avon jadelennox
avon jhango
Now use the pairs to find triples. The rule is that abc is a triple if ab ac and bc are all pairs. What this means is that all three people are Friends of each other in addition to being Friends of you. I have 186 triples, starting with
avon cnoocy colorwheel
avon cnoocy jadelennox
avon cnoocy jhango
avon cnoocy rikchik
avon cnoocy temvald
Note that I've gone from 28 Friends to 113 pairs to 186 triples. This is slow growth. The worst case is on the order of x^n, where x is the number of Friends you have and n is the number of people in the group. If you have 200 Friends, many of whom are also Friends of each other, you could be looking at 10,000 pairs and 500,000 triples. This is the computational complexity
Anyway, repeat the process to get groups of 4. If abc and abd are triples and cd is a pair, then abcd is a group of 4.
Keep going until you've formed the largest groups you can. My largest group is
I have 17 groups of six interconnected Friends. These include:
avon cnoocy colorwheel jadelennox jhango rikchik
chanaleh greenlily kalessin saxikath scwang zenala
cnoocy colorwheel dougo jhango prog rikchik
Friends who show up here are my Tier 2 Friends and appear in a large, faint font. My Tier 2 friends are
I have 75 groups of five interconnected Friends. Friends who first appear here are Tier 3 Friends, and so on.
Loosely, my Tier 1 Friends are connected through MITG&SP. My Tier 2 Friends include some people I know from MITG&SP who are less tightly connected and some people I know from around Somerville. I expect that the two groups would show as different colors on a colored map and that the positions of the names would indicate the groups.
I have ordered a LJ Mindmap for myself to confirm my results. Unfortunately, this shows a second computational complexity of the Mindmaps. As interest spreads, demand for maps will grow exponentially, meaning that eventually so many people will request maps that
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Date: Wednesday, March 24th, 2004 07:01 pm (UTC)First, growth rate: Exponential? 24 hour server logs tell one story:
It's at least geometric.
But I bet you're dyin' to compare notes... ok, you roped me in... I wanna see if you're right...
Tier 1
mrmorse rikchik jadelennox avon cnoocy colorwheel temvald prog jhango saxikath chanaleh kalessin greenlily scwang zenala cmouse blkdrgn mister_nick
Tier 2
katfairy dragonfriek laurens10 tapuz marfta xiphias evelio
Tier 3
cthulhia dougo jessruth
Tier 4
zogathon
(5, 6, and 7 are empty)
I don't think I met your color expectations... but your first tier is south, second tier north. Neato.
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Date: Thursday, March 25th, 2004 08:27 am (UTC)There are some signficant differences between your rankings and mine. Your Tier 1 includes everybody I put in Tiers 1 and 2, with the exception of
You must be defining Tiers differently than I did. My Tier 1 includes everybody in a mutually connected group of 7 Friends. Tier 2 is everyone in a mutually connected group of 6 Friends, and so forth. That's obviously not what you're doing, but at this point what you're doing isn't clear to me.
I'm curious about the numbers you sent me. Your number of sets at each stage was significantly higher than mine. The algorithm I used ensured that the sets were unordered and unique. That is, if abc is a set, then acb is not also a set. I wonder if that accounts for the difference or if there's something else going on. Now that I think about it, it could be that I excluded myself. (I already know that I'm Friends with everyone on my Friends list, so I could ignore myself.)
Having gone through all this, I have a new appreciation for the impact that large groups of well connected Friends makes. It took me several hours to produce my results, and that was with a maximum set of 7. I've been thinking about it and I think that if my largest group was 8 it would have produced so many more combinations that my work probably would have taken 4 times as long to complete.
I knew I was insane to do it by hand, but I didn't realize how insane. Apparently I'm also lucky.
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Date: Thursday, March 25th, 2004 08:43 am (UTC)Your understanding of Tiering is correct. People rise to the highest tier.
I also only track unique sets. Do I exclude the root? I don't remember! If you have a clue on simplifying these calculations... I'm all ears! (Too tired to pay more attention than this right now.) I see a pattern of expansion and then contraction. Indeed, the difference between a "normal" calculation and a "hard" one is like 5-10minutes vs. 5-10days or weeks. There seems to be little in-between.
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Date: Friday, March 26th, 2004 12:49 am (UTC)I am not a skilled set theoreitician. The long and short of this is that I need a faster algorythm. I am looking at seven users of substantial complexity whose requests confound me. More CPUs will not help. I have to find a better way.
So I am following up on your comment about differences in our calculations... perhaps my algoryhtm is wasteful yet. In any case, the better solution for this problem tends along this approach:
Carve a chunk of nodes off the main chunk. Examine the number of interconnections within the new cluster, vs. interconnections back into the main chunk. Subtract the latter from the former. The result tells you how good a cut you've made.
This is apparently a hueristic approach... if I had some shortcuts to get the big picture, perhaps I could clean that sufficiently. I don't know. I'm kind of frustrated. What do you think?
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Date: Friday, April 30th, 2004 10:44 pm (UTC)It seems to me that what you want is a variation on the Apriori algorithm (http://fuzzy.cs.uni-magdeburg.de/~borgelt/doc/apriori/apriori.html), which is used in data mining operations to discover associations among large boolean datasets. The most common example is that it might be run on a store's sales tallies, to discover rules such as 'people who buy beer tend to buy diapers' or similar.
Another more obvious example is on amazon (http://www.amazon.com). When they tell you "People who bought this book tended to also buy these books", and present a list of other books, they used the apriori algorithm to mine that list of books.
You can find an open-source java implementation (http://users.wpi.edu/~peterg/public/random/Apriori.java) on my page, or you can go directly for the Weka Data-mining package (http://www.cs.waikato.ac.nz/ml/weka/) from which I took that file.
I know it's not a direct application; you are going to have to modify things somewhat. Even so, the algorithm you describe sounds quite similar to this, so you might be able to pick up useful optimizations by examining the code.
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Date: Thursday, March 25th, 2004 07:10 am (UTC)Proving, once more with feeling, that somewhere out there for you is a Calling that you're missing. :-)
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Date: Tuesday, April 13th, 2004 03:13 pm (UTC)I know
It's a very, very strange 'Net, no?
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Date: Friday, May 21st, 2004 11:47 pm (UTC)no subject
Date: Thursday, January 6th, 2005 03:26 pm (UTC)What do teal brackets around names mean?
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Date: Monday, May 28th, 2007 09:29 pm (UTC)