X-Git-Url: https://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FGrid.hs;h=efa63418947c308e7bed8c25619dadbc8d9d0a8e;hb=ecb77f944fcba8c8cfe60ca782bc5d9c8ab68cf9;hp=1a436acdc00d9276ceb1e25b7080355577822bf3;hpb=cc10c04deda3bdf54867a9052b638f0bc4b09fbe;p=spline3.git

diff --git a/src/Grid.hs b/src/Grid.hs
index 1a436ac..efa6341 100644
--- a/src/Grid.hs
+++ b/src/Grid.hs
@@ -4,6 +4,8 @@
 module Grid
 where
 
+import Test.QuickCheck (Arbitrary(..), Gen, Positive(..))
+
 import Cube (Cube(Cube))
 import FunctionValues
 import Misc (flatten)
@@ -20,6 +22,13 @@ data Grid = Grid { h :: Double, -- MUST BE GREATER THAN ZERO!
           deriving (Eq, Show)
 
 
+instance Arbitrary Grid where
+    arbitrary = do
+      (Positive h') <- arbitrary :: Gen (Positive Double)
+      fvs <- arbitrary :: Gen [[[Double]]]
+      return (make_grid h' fvs)
+
+
 -- | The constructor that we want people to use. If we're passed a
 --   non-positive grid size, we throw an error.
 make_grid :: Double -> [[[Double]]] -> Grid