Bryan,
mwc-random is really fast. But it eats to much memory. My previous
attempts were to reduce total number of allocations. This package made
this possible, but it increases total memory usage.
Here is the code:
import Text.Printf
import System.Random.MWC
import Control.Applicative
import System.Environment
import Data.Array.Vector
import Control.Monad.ST
randomListU size = runST $ flip uniformArray size =<< create
main = do
[size] <- map read <$> getArgs
printf "%d\n" $ (sumU (randomListU size) :: Int)
And sample tests:
./mwcvec 10000000 +RTS -s
-9198901858466039191
165,312 bytes allocated in the heap
688 bytes copied during GC
17,184 bytes maximum residency (1 sample(s))
19,680 bytes maximum slop
78 MB total memory in use (1 MB lost due to fragmentation)
./mwcvec 100000000 +RTS -s
2242701120799374676
165,704 bytes allocated in the heap
688 bytes copied during GC
17,184 bytes maximum residency (1 sample(s))
19,680 bytes maximum slop
764 MB total memory in use (12 MB lost due to fragmentation)
./mwcvec 1000000000 +RTS -s
mwcvec: out of memory (requested 8000634880 bytes)
I don't know exactly, but is this a normal behavior ?
Thank you,
Vasyl
2010/2/9 Bryan O'Sullivan <b...@serpentine.com>:
> On Tue, Feb 9, 2010 at 4:18 AM, Vasyl Pasternak <vasyl.paster...@gmail.com>
> wrote:
>>
>> I tried to generate memory-efficient list of random numbers, so I've
>> used uvector library for this task.
>
> Use the mwc-random package. It provides a function that does exactly this,
> and produces better quality random numbers with much higher performance
> (1000x faster) than System.Random or even mersenne-random.
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