Re:Show HN: Free Reddit submission scheduling and vote poten...
by jkyle on Thursday June 04, 2015 @08:54AM
(#9658869)
This is absolutely correct. The algorithm is meant to quickly drop posts from the top. Such that even if a post has a record vote score, it still will only remain at the top for a few days.
The amix link above didn't load for me today, but I like this scienceblogs post on the algorithm.[1]
edit
It should also be noted that since reddit is open source, you can always dig right in! [2]
[1] http://scienceblogs.com/builtonfacts/2013/01/16/the-mathemat...
[2] https://github.com/reddit/reddit/blob/master/r2/r2/lib/db/_s...
Re:Show HN: Free Reddit submission scheduling and vote poten...
by pacofvf on Thursday June 04, 2015 @01:20PM
(#9660650)
cpdef double _hot(long ups, long downs, double date):
"""The hot formula. Should match the equivalent function in postgres."""
s = score(ups, downs)
order = log10(max(abs(s), 1))
if s > 0:
sign = 1
elif s < 0:
sign = -1
else:
sign = 0
seconds = date - 1134028003
return round(sign * order + seconds / 45000, 7)
here's the function in question, so yes a newer post with fewer votes than a minutes older post will remain on top.
Re:Show HN: Free Reddit submission scheduling and vote poten...
by ElvisMa on Thursday June 04, 2015 @09:07AM
(#9658949)
not only that, the ranking is also defined by the overall activity in the sub-reddit it is posted in. So you can see a post with fewer upvotes, posted later over a post which has a lot more upvotes posted earlier. Which means, even submissions to very small sub-reddits have a decent chance to be promoted to trending and to r/all even
Re:Show HN: Free Reddit submission scheduling and vote poten...
by jkyle on Thursday June 04, 2015 @09:29AM
(#9659067)
The trending or 'hot' algorithm is a bit different than the "top" algorithm.
I believe you're referring to the 'hot' algorithm which is meant to take velocity into account. Velocity tries to abstract away contextual factors like subreddit activity, number of votes, etc. and represent how quickly, relative to number of participants, a post is 'rising'.
The 'top' algorithm, however, is purely a factor of total vote (up - down) + time.
The number of votes compared to the age is important, but this isn't normalised compared to the current vote rate. There's a significant fluctuation in the number of people on reddit at different times of the day, so when you submit can be important.