From 542abe1c9e351b92f3965ee755e6678ac1f14cf2 Mon Sep 17 00:00:00 2001
From: Mark Wotton <mwotton@gmail.com>
Date: Fri, 22 May 2015 11:15:05 +0700
Subject: [PATCH 1/2] add test for regressions

---
 statistics.cabal          |  1 +
 tests/Tests/Regression.hs | 36 ++++++++++++++++++++++++++++++++++++
 tests/tests.hs            | 17 ++++++++++-------
 3 files changed, 47 insertions(+), 7 deletions(-)
 create mode 100644 tests/Tests/Regression.hs

diff --git a/statistics.cabal b/statistics.cabal
index 6f12ab70..ce17fe7c 100644
--- a/statistics.cabal
+++ b/statistics.cabal
@@ -124,6 +124,7 @@ test-suite tests
     Tests.ApproxEq
     Tests.Correlation
     Tests.Distribution
+    Tests.Regression
     Tests.Function
     Tests.Helpers
     Tests.KDE
diff --git a/tests/Tests/Regression.hs b/tests/Tests/Regression.hs
new file mode 100644
index 00000000..1619f9ae
--- /dev/null
+++ b/tests/Tests/Regression.hs
@@ -0,0 +1,36 @@
+module Tests.Regression
+       ( tests ) where
+
+import           Data.Vector.Unboxed                  (Vector)
+import qualified Data.Vector.Unboxed                  as U
+import           Statistics.Regression
+import           Test.Framework                       (Test, testGroup)
+import           Test.Framework.Providers.QuickCheck2 (testProperty)
+import           Test.QuickCheck
+
+data Predictor = Predictor [Vector Double] (Vector Double)
+  deriving Show
+
+instance Arbitrary Predictor where
+  arbitrary = do
+    -- we pick an arbitrary length N - this is the length the
+    -- predictor vectors and the responder vector will have
+    n <- arbitrary `suchThat` (>0)
+
+    matrix <- listOf1 (vectorOf n $ elements [1,2,3])
+              -- the matrix must have more rows than columns
+              `suchThat` ((>n) . length)
+
+    responder <- vectorOf n (elements [4,5,6])
+
+    return (Predictor (map U.fromList matrix) (U.fromList responder))
+
+tests :: Test
+tests = testGroup "Regression"
+        [ testProperty "OLS test - shape" testOLS ]
+
+
+testOLS :: Predictor -> Bool
+testOLS (Predictor matrix responder) =
+  let (v,double) = olsRegress matrix responder in
+  U.length v == 1 + U.length responder && double >= 0 && double <= 1
diff --git a/tests/tests.hs b/tests/tests.hs
index 128ec2ef..025c3ccb 100644
--- a/tests/tests.hs
+++ b/tests/tests.hs
@@ -1,11 +1,13 @@
-import Test.Framework (defaultMain)
-import qualified Tests.Distribution as Distribution
-import qualified Tests.Function as Function
-import qualified Tests.KDE as KDE
-import qualified Tests.Matrix as Matrix
+import           Test.Framework      (defaultMain)
+import qualified Tests.Correlation   as Correlation
+import qualified Tests.Distribution  as Distribution
+import qualified Tests.Function      as Function
+import qualified Tests.KDE           as KDE
+import qualified Tests.Matrix        as Matrix
 import qualified Tests.NonParametric as NonParametric
-import qualified Tests.Transform as Transform
-import qualified Tests.Correlation as Correlation
+import qualified Tests.Regression    as Regression
+import qualified Tests.Transform     as Transform
+
 
 main :: IO ()
 main = defaultMain [ Distribution.tests
@@ -15,4 +17,5 @@ main = defaultMain [ Distribution.tests
                    , NonParametric.tests
                    , Transform.tests
                    , Correlation.tests
+                   , Regression.tests
                    ]

From de5148146f6460c263a0560cdeea629408b0a6cf Mon Sep 17 00:00:00 2001
From: Mark Wotton <mwotton@gmail.com>
Date: Fri, 22 May 2015 12:25:00 +0700
Subject: [PATCH 2/2] updated tests

---
 tests/Tests/Regression.hs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/tests/Tests/Regression.hs b/tests/Tests/Regression.hs
index 1619f9ae..d3981515 100644
--- a/tests/Tests/Regression.hs
+++ b/tests/Tests/Regression.hs
@@ -3,6 +3,7 @@ module Tests.Regression
 
 import           Data.Vector.Unboxed                  (Vector)
 import qualified Data.Vector.Unboxed                  as U
+import           Debug.Trace                          (trace)
 import           Statistics.Regression
 import           Test.Framework                       (Test, testGroup)
 import           Test.Framework.Providers.QuickCheck2 (testProperty)
@@ -15,11 +16,11 @@ instance Arbitrary Predictor where
   arbitrary = do
     -- we pick an arbitrary length N - this is the length the
     -- predictor vectors and the responder vector will have
-    n <- arbitrary `suchThat` (>0)
+    n <- arbitrary `suchThat` (>1)
 
     matrix <- listOf1 (vectorOf n $ elements [1,2,3])
               -- the matrix must have more rows than columns
-              `suchThat` ((>n) . length)
+              `suchThat` ((<n) . length)
 
     responder <- vectorOf n (elements [4,5,6])
 
@@ -33,4 +34,8 @@ tests = testGroup "Regression"
 testOLS :: Predictor -> Bool
 testOLS (Predictor matrix responder) =
   let (v,double) = olsRegress matrix responder in
-  U.length v == 1 + U.length responder && double >= 0 && double <= 1
+  let vlen = U.length v
+      mlen = length matrix in
+  if (vlen == mlen+1 && double >=0 && double <= 1)
+  then True
+  else trace (show ("ols", vlen,mlen,U.length (head matrix), double)) False