#1272: newStdGen returns the same value on successive calls
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Reporter: guest | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.6
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: Unknown
Os: Unknown |
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Comment (by guest):
{{{
mkStdRNG :: Integer -> IO StdGen
mkStdRNG o = do
ct <- getCPUTime
(TOD sec _) <- getClockTime
return (createStdGen (sec * 12345 + ct + o))
}}}
The problem here is that {{{getCPUTime}}} often returns zero. Possibly
because this happens at the start of the program, and with too low
resolution. Experimenting a bit, it appears that the smallest non-zero
value for getCPUTime is 4*10^9, i.e. a resolution of 4ms?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1272>
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