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by Daniel Berger.
Original Post: Memoizing to disk
Feed Title: Testing 1,2,3...
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With an idea from Mauricio Fernandez and some help from Ara Howard, the memoize package now supports an optional second argument - a file name. If provided results are cached to the file instead of memory.
This is advantageous if you want a persistant store between sessions for, say, a web framework, or if you just want to conserve memory. Behind the scenes it uses Marshal, which is actually incredibly fast, to the point where you shouldn't really notice a speed difference unless you go over 1000 nodes, or so I'm told. That does have the drawback of not being compatible between different versions of Ruby, however.
require "memoize"
include Memoize
def fib(n)
return n if n < 2
fib(n-1) + fib(n-2)
end
memoize(:fib, "fib.cache")
p fib(10) # 55
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