Convert the zoom function to use Values3D.

[spline3.git] / src / Grid.hs

diff --git a/src/Grid.hs b/src/Grid.hs
index 63b2cfa122bc6ba5bbb9d496b77f1a00466eebb6..3d636b53a780f465b515c6e45f8ee53b6e7f10ba 100644 (file)
--- a/src/Grid.hs
+++ b/src/Grid.hs
@@ -12,27 +12,29 @@ import Misc (flatten)
 import Point (Point)
 import Tetrahedron (polynomial)
 import ThreeDimensional (contains_point)
+import Values (Values3D, dims, empty3d, zoom_shape)
 
+import qualified Data.Array.Repa as R
 
 -- | Our problem is defined on a Grid. The grid size is given by the
 --   positive number h. The function values are the values of the
 --   function at the grid points, which are distance h from one
 --   another in each direction (x,y,z).
 data Grid = Grid { h :: Double, -- MUST BE GREATER THAN ZERO!
-                   function_values :: [[[Double]]] }
+                   function_values :: Values3D }
           deriving (Eq, Show)
 
 
 instance Arbitrary Grid where
     arbitrary = do
       (Positive h') <- arbitrary :: Gen (Positive Double)
-      fvs <- arbitrary :: Gen [[[Double]]]
+      fvs <- arbitrary :: Gen Values3D
       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
+make_grid :: Double -> Values3D -> Grid
 make_grid grid_size values
     | grid_size <= 0 = error "grid size must be positive"
     | otherwise = Grid grid_size values
@@ -40,24 +42,21 @@ make_grid grid_size values
 
 -- | Creates an empty grid with grid size 1.
 empty_grid :: Grid
-empty_grid = Grid 1 [[[]]]
+empty_grid = Grid 1 empty3d
 
 
 -- | Returns a three-dimensional list of cubes centered on the grid
 --   points of g with the appropriate 'FunctionValues'.
 cubes :: Grid -> [[[Cube]]]
 cubes g
-    | fvs == [[[]]] = [[[]]]
-    | head fvs == [[]] = [[[]]]
+    | xsize == 0 || ysize == 0 || zsize == 0 = [[[]]]
     | otherwise =
         [[[ Cube (h g) i j k (make_values fvs i j k) | i <- [0..xsize]]
               | j <- [0..ysize]]
               | k <- [0..zsize]]
     where
       fvs = function_values g
-      zsize = (length fvs) - 1
-      ysize = length (head fvs) - 1
-      xsize = length (head $ head fvs) - 1
+      (xsize, ysize, zsize) = dims fvs
 
 
 -- | Takes a grid and a position as an argument and returns the cube
@@ -84,27 +83,24 @@ find_containing_cubes g p =
       contains_our_point = flip contains_point p
 
 
-
-zoom :: Grid -> Int -> [[[Double]]]
+zoom :: Grid -> Int -> Values3D
 zoom g scale_factor
-    | fvs == [[[]]] = []
-    | head fvs == [[]] = []
+    | xsize == 0 || ysize == 0 || zsize == 0 = empty3d
     | otherwise =
-        [[[f p | i <- [0..scaled_zsize],
-                 let i' = scale_dimension i,
-                 let j' = scale_dimension j,
-                 let k' = scale_dimension k,
-                 let p = (i', j', k') :: Point,
-                 let c = (find_containing_cubes g p) !! 0,
-                 let t = (find_containing_tetrahedra c p) !! 0,
-                 let f = polynomial t]
-                 | j <- [0..scaled_ysize]]
-                   | k <- [0..scaled_xsize]]
-  where
-    scale_dimension :: Int -> Double
-    scale_dimension x = (fromIntegral x) / (fromIntegral scale_factor)
-
-    fvs = function_values g
-    scaled_zsize = ((length fvs) - 1) * scale_factor
-    scaled_ysize = (length (head fvs) - 1) * scale_factor
-    scaled_xsize = (length (head $ head fvs) - 1) * scale_factor
+        R.traverse arr transExtent (\_ -> newlookup)
+          where
+            fvs = function_values g
+            (xsize, ysize, zsize) = dims fvs
+            arr = fvs
+            transExtent = zoom_shape scale_factor
+            newlookup :: R.DIM3 -> Double
+            newlookup (R.Z R.:. i R.:. j R.:. k) =
+                f p
+                  where
+                    i' = fromIntegral i
+                    j' = fromIntegral j
+                    k' = fromIntegral k
+                    p = (i', j', k') :: Point
+                    c = head (find_containing_cubes g p)
+                    t = head (find_containing_tetrahedra c p)
+                    f = polynomial t