You may find that your scores have a tendency to grow without bounds, especially if you're using adaptive scoring. If scores get too big, they lose all meaning---they simply max out and it's difficult to use them in any sensible way.
Gnus provides a mechanism for decaying scores to help with this problem.
When score files are loaded and gnus-decay-scores
is
non-nil
, Gnus will run the score files through the decaying
mechanism thereby lowering the scores of all non-permanent score rules.
The decay itself if performed by the gnus-decay-score-function
function, which is gnus-decay-score
by default. Here's the
definition of that function:
(defun gnus-decay-score (score) "Decay SCORE. This is done according to `gnus-score-decay-constant' and `gnus-score-decay-scale'." (floor (- score (* (if (< score 0) 1 -1) (min (abs score) (max gnus-score-decay-constant (* (abs score) gnus-score-decay-scale)))))))
gnus-score-decay-constant
is 3 by default and
gnus-score-decay-scale
is 0.05. This should cause the following:
If you don't like this decay function, write your own. It is called with the score to be decayed as its only parameter, and it should return the new score, which should be an integer.
Gnus will try to decay scores once a day. If you haven't run Gnus for four days, Gnus will decay the scores four times, for instance.
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