Re: [Civil-devel]map memory

Just jumping in here.  I've got a lot to do, but I'm alive.

Sez Mike Earl:
> 2) Another possibility; objects are large, but *pointers* are quite
> small.  If there are a small number of hex types, keep a dictionary of
> the ones being used, and put them in the map instead of creating new
> ones.  We'd only have 1 copy of any duplicated hexes, which would reduce
> the memory required dramatically.   Haven't really thought this all the
> way through, but it might be useful...

Sounds like a Flyweight.

> btw: in testing some of this, I found a nice python tidbit.  To
> initalize a 320x200 array of blank objects, you can just take
> 
> [[None] * 320] * 200
> 
> This operation is also very, very fast, for some reason.

Yeah, but watch out:
>>> l = [[None] * 320] * 200
>>> l[0][0] = 1
>>> l[0][0]
1
>>> l[1][0]
1
>>>

Check it out:
>>> l = map(list, list(((None,)*320,)*200))
>>> l[0][0] = 1
>>> l[0][0]
1
>>> l[1][0]
>>> 

It's almost lisp!

Peace,
  Kalle
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