3 ms·

That's close to the current version, but a little out of date. Here's the code running now: (= gravity* 1.8 timebase* 120 front-threshold* 1 nourl-f

by pg 16y ago

That's close to the current version, but a little out of date. Here's the code running now: (= gravity* 1.8 timebase* 120 front-threshold* 1 nourl-factor* .4 lightweight-factor* .17 gag-factor* .1) (def frontpage-rank (s (o scorefn realscore) (o gravity gravity*)) (* (/ (let base (- (scorefn s) 1) (if (> base 0) (expt base .8) base)) (expt (/ (+ (item-age s) timebase*) 60) gravity)) (if (no (in s!type 'story 'poll)) .8 (blank s!url) nourl-factor* (mem 'bury s!keys) .001 (* (contro-factor s) (if (mem 'gag s!keys) gag-factor* (lightweight s) lightweight-factor* 1)))))

sahillavingia 16y ago
For those who aren't well versed in Arc or Lisp, could someone go through the differences?
- tel 16y ago
  Appears to be substantially identical to what's outlined in the post. The only changes are in the penalties dealt out by the type of story, inclusion of a url, buried status, gagged status, and the operation of penalties due to the contro(versial?)-factor function. If you're just submitting interesting URLs and worry about them being shunted off the main page by gravity then there are no practical differences.
  - pg 16y ago
    The gag tag doesn't mean "gagged." It means the post is a gag, in the sense of a joke. Sorry I can't be more transparent about how contro-factor is calculated, incidentally. Its purpose is to recognize flamewars.
    - davi 16y ago
      I'm curious about how you evaluate prospective algorithm changes. Do you roll out a change you think should work and then monitor, or do you have a corpus of e.g. flame wars you test against?
      - pg 16y ago
        There's a repl on the server, and I test tweaks on the live site.
        techbio 16y ago
        Do you have a dashboard of some kind to visualize your tests effects? I am curious about the broad kind of insight one could have with such a programmatic access to this community. Perhaps I missed an essay about HN/REPL?
pypyguy 16y ago
Any genius willing to translate this to python?
- zackattack 16y ago
  I would prefer PHP but seconded
  - sstrudeau 16y ago
    This is pretty trivial but sure, something like: function calculate_score($votes, $item_hour_age, $gravity=1.8) { return ($votes - 1) / pow(($item_hour_age+2), $gravity); }
    - mkramlich 16y ago
      it's interested to see such a direction comparison of PHP to Python. PHP is very similar to the Python except with more syntax noise. :) And probably worse docs. And worse namespacing, etc. ;)
      - Xipe 16y ago
        Whatever failings PHP may have its docs are not among them.
- sstrudeau 16y ago
  There's a python implementation in the original article: def calculate_score(votes, item_hour_age, gravity=1.8): return (votes - 1) / pow((item_hour_age+2), gravity)
EGreg 16y ago
do you guys take logs of both sides, so you don't have to keep updating the scores of all the previously posted items? I mean, if all that matters is how big the scores are relative to one another, then A > B <=> log A > log B (since A and B are positive). You'll just have to add a G*log(T+2) to the log(P) for new items, which can go on for a very long time. ... T is the time since some arbitrary point. I think I may have just reinvented the way reddit does it :P
- EGreg 16y ago
  in fact, as someone else said if you then make T = the number of submissions / votes since the beginning, people would be able to post at midnight and it would still have a "fair" chance of being ranked along with the other articles posted at busier times.

by pg 16y ago

sahillavingia 16y ago

For those who aren't well versed in Arc or Lisp, could someone go through the differences?

tel 16y ago
Appears to be substantially identical to what's outlined in the post. The only changes are in the penalties dealt out by the type of story, inclusion of a url, buried status, gagged status, and the operation of penalties due to the contro(versial?)-factor function. If you're just submitting interesting URLs and worry about them being shunted off the main page by gravity then there are no practical differences.
- pg 16y ago
  The gag tag doesn't mean "gagged." It means the post is a gag, in the sense of a joke. Sorry I can't be more transparent about how contro-factor is calculated, incidentally. Its purpose is to recognize flamewars.
  - davi 16y ago
    I'm curious about how you evaluate prospective algorithm changes. Do you roll out a change you think should work and then monitor, or do you have a corpus of e.g. flame wars you test against?
    - pg 16y ago
      There's a repl on the server, and I test tweaks on the live site.
      - techbio 16y ago
        Do you have a dashboard of some kind to visualize your tests effects? I am curious about the broad kind of insight one could have with such a programmatic access to this community. Perhaps I missed an essay about HN/REPL?

pypyguy 16y ago

Any genius willing to translate this to python?

zackattack 16y ago
I would prefer PHP but seconded
- sstrudeau 16y ago
  This is pretty trivial but sure, something like: function calculate_score($votes, $item_hour_age, $gravity=1.8) { return ($votes - 1) / pow(($item_hour_age+2), $gravity); }
  - mkramlich 16y ago
    it's interested to see such a direction comparison of PHP to Python. PHP is very similar to the Python except with more syntax noise. :) And probably worse docs. And worse namespacing, etc. ;)
    - Xipe 16y ago
      Whatever failings PHP may have its docs are not among them.
sstrudeau 16y ago
There's a python implementation in the original article: def calculate_score(votes, item_hour_age, gravity=1.8): return (votes - 1) / pow((item_hour_age+2), gravity)

EGreg 16y ago

do you guys take logs of both sides, so you don't have to keep updating the scores of all the previously posted items? I mean, if all that matters is how big the scores are relative to one another, then A > B <=> log A > log B (since A and B are positive). You'll just have to add a G*log(T+2) to the log(P) for new items, which can go on for a very long time. ... T is the time since some arbitrary point. I think I may have just reinvented the way reddit does it :P

EGreg 16y ago
in fact, as someone else said if you then make T = the number of submissions / votes since the beginning, people would be able to post at midnight and it would still have a "fair" chance of being ranked along with the other articles posted at busier times.