module Data.Metrics.Histogram (
Histogram,
histogram,
exponentiallyDecayingHistogram,
uniformHistogram,
module Data.Metrics.Types
) where
import Control.Monad.Primitive
import qualified Data.Metrics.Histogram.Internal as P
import Data.Metrics.Internal
import Data.Metrics.Types
import Data.Metrics.Reservoir (Reservoir)
import Data.Metrics.Reservoir.Uniform (unsafeReservoir)
import Data.Metrics.Reservoir.ExponentiallyDecaying (reservoir)
import Data.Primitive.MutVar
import Data.Time.Clock
import Data.Time.Clock.POSIX
import System.Random.MWC
data Histogram m = Histogram
{ fromHistogram :: MV m P.Histogram
, histogramGetSeconds :: m NominalDiffTime
}
instance PrimMonad m => Clear m (Histogram m) where
clear h = do
t <- histogramGetSeconds h
updateRef (fromHistogram h) $ P.clear t
instance PrimMonad m => Update m (Histogram m) Double where
update h x = do
t <- histogramGetSeconds h
updateRef (fromHistogram h) $ P.update x t
instance PrimMonad m => Count m (Histogram m) where
count h = readMutVar (fromHistogram h) >>= return . P.count
instance PrimMonad m => Statistics m (Histogram m) where
mean h = applyWithRef (fromHistogram h) P.mean
stddev h = applyWithRef (fromHistogram h) P.stddev
variance h = applyWithRef (fromHistogram h) P.variance
maxVal h = readMutVar (fromHistogram h) >>= return . P.maxVal
minVal h = readMutVar (fromHistogram h) >>= return . P.minVal
instance PrimMonad m => TakeSnapshot m (Histogram m) where
snapshot h = applyWithRef (fromHistogram h) P.snapshot
histogram :: PrimMonad m => m NominalDiffTime -> Reservoir -> m (Histogram m)
histogram t r = do
v <- newMutVar $ P.histogram r
return $ Histogram v t
uniformHistogram :: Seed -> IO (Histogram IO)
uniformHistogram s = histogram getPOSIXTime $ unsafeReservoir s 1028
exponentiallyDecayingHistogram :: IO (Histogram IO)
exponentiallyDecayingHistogram = do
t <- getPOSIXTime
s <- createSystemRandom >>= save
histogram getPOSIXTime $ reservoir 0.015 1028 t s
uniformSampler :: Seed -> P.Histogram
uniformSampler s = P.histogram (unsafeReservoir s 1028)
nan :: Double
nan = 0 / 0