> Basically I need to represent a mapping from the set of the n first
> positive integers to itself, with n ~= (expt 10 6).  I have try with
> an hash-table and with an array, but I run out of memory.

An array of the integers between 0-1,000,000 shouldn't be hard to
handle.  You should tell MAKE-ARRAY that you want to store small
integers (called 'fixnums', since they use only a fixed number of
bits).  So you would say:

(make-array (expt 10 6) :element-type 'fixnum)

This means that when you store a number into the array, Lisp won't
create an extra 'box' to go around the number, reminding itself what
type that element is, since it is certainly a fixnum.  Not having all
those boxes around should save you some memory.


Wheeler
-- 
Wheeler Ruml, Eng Sci Lab Rm 420, <eecs.harvard.edu, at ruml> (617) 495-2081 (voice)
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