From c3147a6b56556af23e8d52931704a88496ed1eb3 Mon Sep 17 00:00:00 2001
From: Nicolas Bacquey <nicolas.bacquey@tweag.io>
Date: Wed, 9 Jan 2019 17:24:17 +0100
Subject: [PATCH 1/2] Added linear regression to compute execution time

Fixes #40, Added information to report display
---
 src/Hyperion/Analysis.hs    | 12 +++++++++++-
 src/Hyperion/PrintReport.hs |  6 +++++-
 src/Hyperion/Report.hs      |  3 +++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/Hyperion/Analysis.hs b/src/Hyperion/Analysis.hs
index a38a61b..4777bfd 100644
--- a/src/Hyperion/Analysis.hs
+++ b/src/Hyperion/Analysis.hs
@@ -14,6 +14,7 @@ import Control.Lens
   , foldMapOf
   , folded
   , to
+  , toListOf
   )
 
 import Control.Lens.Each
@@ -23,6 +24,8 @@ import Hyperion.Benchmark
 import Hyperion.Internal
 import Hyperion.Measurement
 import Hyperion.Report
+import Statistics.Regression
+import qualified Data.Vector.Unboxed as UV
 
 identifiers :: Fold Benchmark BenchmarkId
 identifiers = go []
@@ -47,7 +50,10 @@ analyze ident samp = Report
     , _reportBenchParams =
         map (\(Parameter x) -> fromEnum x) $ benchmarkParameters ident
     , _reportTimeInNanos =
-        totalDuration / trueNumIterations
+        totalDuration / trueNumIterations 
+    , _linearRegressionTime = slope
+    , _linearRegressionConstant = yIntercept
+    , _linearRegressionConfidence = determinationCoefficient
     , _reportCycles = Nothing
     , _reportAlloc = Nothing
     , _reportGarbageCollections = Nothing
@@ -64,3 +70,7 @@ analyze ident samp = Report
         Sum
         (foldMapOf (measurements.each.batchSize.to realToFrac))
         samp
+    ([slope,yIntercept],determinationCoefficient) = (\(v,r) -> (UV.toList v,r)) $ olsRegress [batchSizesVect] durationsVect 
+      where
+        batchSizesVect = UV.fromList $ fromIntegral <$> toListOf (measurements.each.batchSize) samp
+        durationsVect = UV.fromList $ fromIntegral <$> toListOf (measurements.each.duration) samp
diff --git a/src/Hyperion/PrintReport.hs b/src/Hyperion/PrintReport.hs
index e9f8bc2..27e1da8 100644
--- a/src/Hyperion/PrintReport.hs
+++ b/src/Hyperion/PrintReport.hs
@@ -14,7 +14,11 @@ import Text.PrettyPrint.ANSI.Leijen
 formatReport :: Report -> Doc
 formatReport report =
            green (bold (text (unpack (view reportBenchName report)))) <> line
-           <> (indent 2 $ text ("Bench time: " ++ prettyNanos (view reportTimeInNanos report)))
+           <> (indent 2 $ text ("Bench time: " ++ prettyNanos (view reportTimeInNanos report))) <> line
+           <> (indent 2 $ text ("Computed with linear regression: ")) <> line
+           <> (indent 4 $ text ("Bench time: " ++ prettyNanos (view linearRegressionTime report))) <> line
+           <> (indent 4 $ text ("Constant factor: " ++ prettyNanos (view linearRegressionConstant report))) <> line
+           <> (indent 4 $ text ("Confidence: " ++ showFFloat (Just 4) (view linearRegressionConfidence report) ""))
            <> line
   where
     show2decs x= showFFloat (Just 2) x ""
diff --git a/src/Hyperion/Report.hs b/src/Hyperion/Report.hs
index f5de886..949aec1 100644
--- a/src/Hyperion/Report.hs
+++ b/src/Hyperion/Report.hs
@@ -25,6 +25,9 @@ data Report = Report
   { _reportBenchName :: !Text
   , _reportBenchParams :: [Int]
   , _reportTimeInNanos :: !Double
+  , _linearRegressionTime :: !Double
+  , _linearRegressionConstant :: !Double
+  , _linearRegressionConfidence :: !Double
   , _reportCycles :: !(Maybe Double)
   , _reportAlloc :: !(Maybe Int64)
   , _reportGarbageCollections :: !(Maybe Int64)

From 1ca4c3bba006ca1afeb82c34eb132df9858040c3 Mon Sep 17 00:00:00 2001
From: Arnaud Spiwack <arnaud@spiwack.net>
Date: Wed, 9 Jan 2019 21:18:11 +0100
Subject: [PATCH 2/2] Update src/Hyperion/Analysis.hs

Co-Authored-By: nbacquey <38809035+nbacquey@users.noreply.github.com>
---
 src/Hyperion/Analysis.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Hyperion/Analysis.hs b/src/Hyperion/Analysis.hs
index 4777bfd..5c0c465 100644
--- a/src/Hyperion/Analysis.hs
+++ b/src/Hyperion/Analysis.hs
@@ -70,7 +70,7 @@ analyze ident samp = Report
         Sum
         (foldMapOf (measurements.each.batchSize.to realToFrac))
         samp
-    ([slope,yIntercept],determinationCoefficient) = (\(v,r) -> (UV.toList v,r)) $ olsRegress [batchSizesVect] durationsVect 
+    ([slope,yIntercept],determinationCoefficient) = over _1 UV.toList $ olsRegress [batchSizesVect] durationsVect 
       where
         batchSizesVect = UV.fromList $ fromIntegral <$> toListOf (measurements.each.batchSize) samp
         durationsVect = UV.fromList $ fromIntegral <$> toListOf (measurements.each.duration) samp