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User:Jesse/NewFrecency: Difference between revisions
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'''Frecency''' is a measure that combines frequency and recency. | |||
== Problems with the | This page describes a frecency measure based on exponential decay, and a way to store and update this measure efficiently. | ||
== Problems with the old algorithm == | |||
https://developer.mozilla.org/en/The_Places_frecency_algorithm | https://developer.mozilla.org/en/The_Places_frecency_algorithm | ||
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That takes care of the buckets and sampling. It could be implemented by storing the URL frecency score, and having an idle-daily job that multiplies all scores by (e ^ (-(ln 2) / 30)) = 0.977. | That takes care of the buckets and sampling. It could be implemented by storing the URL frecency score, and having an idle-daily job that multiplies all scores by (e ^ (-(ln 2) / 30)) = 0.977. | ||
== Efficient computation == | |||
But with an additional trick, ''no recomputation is necessary''. The trick is to store in the database something with units of date. | But with an additional trick, ''no recomputation is necessary''. The trick is to store in the database something with units of date. | ||
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* Doesn't emulate the "slowing decay" of the current bucket weights. | * Doesn't emulate the "slowing decay" of the current bucket weights. | ||
** Could be emulated by having two exponential decays with different rates, if desired. | ** Could be emulated by having two exponential decays with different rates, if desired. | ||
== Implementation == | |||
* Gecko - HTTP cache: [https://hg.mozilla.org/mozilla-central/file/b40296602083/netwerk/cache2/CacheEntry.cpp#l1497 in CacheEntry::BackgroundOp] | |||
* Firefox - URL history: Still uses the old algorithm ([https://bugzilla.mozilla.org/show_bug.cgi?id=704025 bug 704025]) | |||