bertram.felgenhauer at googlemail.com
Mon Feb 13 20:32:44 CET 2012
Serge D. Mechveliani wrote:
> Who can tell, please, how read string :: Integer
> is implemented in ghc-7.4.1 ?
> Is it linked from the GMP (Gnu Multi-Precision) library?
I believe your numbers simply were not large enough. I changed
strs n to be
strs n = if n == 0 then [""]
[d : ds | ds <- strs (pred n), d <- digits]
(which changes the answer but avoids holding on to tons of memory)
and ran the program for m = powers of 2 up to 128:
1 real 0m0.392s
2 real 0m0.447s
4 real 0m0.575s
8 real 0m0.995s
16 real 0m1.885s
32 real 0m3.695s
64 real 0m7.826s
128 real 0m17.344s
(best run out of 9 each time)
This looks super-linear already; in the end it should be quadratic.
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