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Re: Node Tension

by educated_foo (Vicar)
on May 24, 2002 at 15:18 UTC ( [id://169100] : note . print w/replies, xml ) Need Help??

in reply to Node Tension

Your formula is certainly much simpler than giulienk's, but I think it may be too simple. In particular, I don't think a +5/-5 node has the same amount of tension as a +95/-5 node. I'd say that a normalized version of your "tension" would be an improvement:
$t = abs($plus - $minus)/($plus + $minus)
Update: Hossman is, of course, right. This should be inverted, like so:
$real_t = 1 - $t
I guess $t is a measure of blandness or something...

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Re: Re: Node Tension
by mojotoad (Monsignor) on May 24, 2002 at 15:25 UTC
    Here's how I was picturing tension: Imagine an object floating free in space. Plus and minus votes represent the magnitude of force pulling on the object in opposite directions. Overwhelming agreement in one direction or the other will merely cause the object to accelerate through space in that direction, rather than threatening to pull the object apart. In this model, +95/-5 would have the same tension as a +5/-5 node, but would be moving much more swiftly through space.

    Having said that, I agree that there's something that might be valuable to capture in the difference between the two examples. Perhaps tension isn't the right word?



      Everything went worng, just as foreseen.

      I get pleasing results with this formula:
      sub tension { my ($hi, $lo) = @_; $lo or return 0; 2 * log($lo)/log($hi + .1); }
      where $hi is the higher number of votes (whichever direction) and $lo is the number of votes in the other direction. Any result above 1 represents an interesting amount of tension, IMO. Here's a table of results:
      Hi #Lo #Tension
      3 31.9420
      8 31.0504
      8 81.9881
      20 30.7322
      20 81.3860
      50 30.5614
      50 81.0626
      90 30.4882
      90 80.9240

      Caution: Contents may have been coded under pressure.
        That looks pretty good, except it seems to lose the magnitude of the tension. 3 vs 3, 8 vs 8, 50 vs 50 all have similar results.

        (of course that's probably just me visually eyeballing sig figs along a log curve...)


Re: Re: Node Tension
by hossman (Prior) on May 25, 2002 at 05:26 UTC
    $t = abs($plus - $minus)/($plus + $minus)

    Wouldn't that make every node with an equal number of ++/-- votes have a tension of 0? wouldn't that defeat the purpose of "tension" ?