X-Git-Url: https://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FCube.hs;h=077fbbc50180ffbea5e6e000060ae990545fa429;hb=3d197ab1a23d654d60617db6559daed195f1e016;hp=2ec9e4848318fb12135309900e5505df20f3614e;hpb=574a15e7ccfa3109f06fa05ed09e2282a03a7dad;p=spline3.git

diff --git a/src/Cube.hs b/src/Cube.hs
index 2ec9e48..077fbbc 100644
--- a/src/Cube.hs
+++ b/src/Cube.hs
@@ -1,6 +1,9 @@
 module Cube
 where
 
+import Data.List ( (\\) )
+import Test.QuickCheck (Arbitrary(..), Gen, Positive(..), choose)
+
 import Cardinal
 import qualified Face (Face(Face, v0, v1, v2, v3))
 import FunctionValues
@@ -12,10 +15,25 @@ data Cube = Cube { h :: Double,
                    i :: Int,
                    j :: Int,
                    k :: Int,
-                   fv :: FunctionValues }
+                   fv :: FunctionValues,
+                   tetrahedra_volume :: Double }
             deriving (Eq)
 
 
+instance Arbitrary Cube where
+    arbitrary = do
+      (Positive h') <- arbitrary :: Gen (Positive Double)
+      i' <- choose (coordmin, coordmax)
+      j' <- choose (coordmin, coordmax)
+      k' <- choose (coordmin, coordmax)
+      fv' <- arbitrary :: Gen FunctionValues
+      (Positive tet_vol) <- arbitrary :: Gen (Positive Double)
+      return (Cube h' i' j' k' fv' tet_vol)
+        where
+          coordmin = -268435456 -- -(2^29 / 2)
+          coordmax = 268435456  -- +(2^29 / 2)
+
+
 instance Show Cube where
     show c =
         "Cube_" ++ subscript ++ "\n" ++
@@ -35,7 +53,7 @@ instance Show Cube where
 
 -- | Returns an empty 'Cube'.
 empty_cube :: Cube
-empty_cube = Cube 0 0 0 0 empty_values
+empty_cube = Cube 0 0 0 0 empty_values 0
 
 
 -- | The left-side boundary of the cube. See Sorokina and Zeilfelder,
@@ -88,7 +106,7 @@ zmax c = (2*k' + 1)*delta / 2
 
 instance ThreeDimensional Cube where
     -- | The center of Cube_ijk coincides with v_ijk at
-    --   (ih, jh, kh). See Sorokina and Zeilfelder, p. 76.    
+    --   (ih, jh, kh). See Sorokina and Zeilfelder, p. 76.
     center c = (x, y, z)
            where
              delta = h c
@@ -101,13 +119,13 @@ instance ThreeDimensional Cube where
 
     -- | It's easy to tell if a point is within a cube; just make sure
     --   that it falls on the proper side of each of the cube's faces.
-    contains_point c p
-        | (x_coord p) < (xmin c) = False
-        | (x_coord p) > (xmax c) = False
-        | (y_coord p) < (ymin c) = False
-        | (y_coord p) > (ymax c) = False
-        | (z_coord p) < (zmin c) = False
-        | (z_coord p) > (zmax c) = False
+    contains_point c (x, y, z)
+        | x < (xmin c) = False
+        | x > (xmax c) = False
+        | y < (ymin c) = False
+        | y > (ymax c) = False
+        | z < (zmin c) = False
+        | z > (zmax c) = False
         | otherwise = True
 
 
@@ -181,9 +199,14 @@ right_face c = Face.Face v0' v1' v2' v3'
       v3' = (center c) + (-delta, delta, -delta)
 
 
+make_tetrahedron :: Cube -> Point -> Point -> Point -> Point -> Tetrahedron
+make_tetrahedron c v0 v1 v2 v3 =
+    Tetrahedron (Cube.fv c) v0 v1 v2 v3 (tetrahedra_volume c)
+
+
 tetrahedron0 :: Cube -> Tetrahedron
 tetrahedron0 c =
-    Tetrahedron (Cube.fv c) v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (front_face c)
@@ -192,7 +215,7 @@ tetrahedron0 c =
 
 tetrahedron1 :: Cube -> Tetrahedron
 tetrahedron1 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (front_face c)
@@ -202,7 +225,7 @@ tetrahedron1 c =
 
 tetrahedron2 :: Cube -> Tetrahedron
 tetrahedron2 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (front_face c)
@@ -212,7 +235,7 @@ tetrahedron2 c =
 
 tetrahedron3 :: Cube -> Tetrahedron
 tetrahedron3 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (front_face c)
@@ -222,7 +245,7 @@ tetrahedron3 c =
 
 tetrahedron4 :: Cube -> Tetrahedron
 tetrahedron4 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (top_face c)
@@ -232,7 +255,7 @@ tetrahedron4 c =
 
 tetrahedron5 :: Cube -> Tetrahedron
 tetrahedron5 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (top_face c)
@@ -242,17 +265,19 @@ tetrahedron5 c =
 
 tetrahedron6 :: Cube -> Tetrahedron
 tetrahedron6 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (top_face c)
       v2' = Face.v2 (top_face c)
       v3' = Face.v3 (top_face c)
-      fv' = rotate cwy $ rotate cwz $ rotate cwz $ Tetrahedron.fv (tetrahedron0 c)
+      fv' = rotate cwy $ rotate cwz
+                       $ rotate cwz
+                       $ Tetrahedron.fv (tetrahedron0 c)
 
 tetrahedron7 :: Cube -> Tetrahedron
 tetrahedron7 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (top_face c)
@@ -262,27 +287,29 @@ tetrahedron7 c =
 
 tetrahedron8 :: Cube -> Tetrahedron
 tetrahedron8 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (back_face c)
       v2' = Face.v0 (back_face c)
       v3' = Face.v1 (back_face c)
-      fv' = rotate cwy $ rotate cwy $ (Tetrahedron.fv (tetrahedron0 c))
+      fv' = rotate cwy $ rotate cwy $ Tetrahedron.fv (tetrahedron0 c)
 
 tetrahedron9 :: Cube -> Tetrahedron
 tetrahedron9 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (back_face c)
       v2' = Face.v1 (back_face c)
       v3' = Face.v2 (back_face c)
-      fv' = rotate cwy $ rotate cwy $ rotate cwx $ Tetrahedron.fv (tetrahedron0 c)
+      fv' = rotate cwy $ rotate cwy
+                       $ rotate cwx
+                       $ Tetrahedron.fv (tetrahedron0 c)
 
 tetrahedron10 :: Cube -> Tetrahedron
 tetrahedron10 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (back_face c)
@@ -296,7 +323,7 @@ tetrahedron10 c =
 
 tetrahedron11 :: Cube -> Tetrahedron
 tetrahedron11 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (back_face c)
@@ -309,7 +336,7 @@ tetrahedron11 c =
 
 tetrahedron12 :: Cube -> Tetrahedron
 tetrahedron12 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (down_face c)
@@ -320,7 +347,7 @@ tetrahedron12 c =
 
 tetrahedron13 :: Cube -> Tetrahedron
 tetrahedron13 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (down_face c)
@@ -331,7 +358,7 @@ tetrahedron13 c =
 
 tetrahedron14 :: Cube -> Tetrahedron
 tetrahedron14 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (down_face c)
@@ -344,7 +371,7 @@ tetrahedron14 c =
 
 tetrahedron15 :: Cube -> Tetrahedron
 tetrahedron15 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (down_face c)
@@ -355,7 +382,7 @@ tetrahedron15 c =
 
 tetrahedron16 :: Cube -> Tetrahedron
 tetrahedron16 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (right_face c)
@@ -366,7 +393,7 @@ tetrahedron16 c =
 
 tetrahedron17 :: Cube -> Tetrahedron
 tetrahedron17 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (right_face c)
@@ -377,7 +404,7 @@ tetrahedron17 c =
 
 tetrahedron18 :: Cube -> Tetrahedron
 tetrahedron18 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (right_face c)
@@ -390,7 +417,7 @@ tetrahedron18 c =
 
 tetrahedron19 :: Cube -> Tetrahedron
 tetrahedron19 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (right_face c)
@@ -402,7 +429,7 @@ tetrahedron19 c =
 
 tetrahedron20 :: Cube -> Tetrahedron
 tetrahedron20 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (left_face c)
@@ -413,7 +440,7 @@ tetrahedron20 c =
 
 tetrahedron21 :: Cube -> Tetrahedron
 tetrahedron21 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (left_face c)
@@ -424,7 +451,7 @@ tetrahedron21 c =
 
 tetrahedron22 :: Cube -> Tetrahedron
 tetrahedron22 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (left_face c)
@@ -437,7 +464,7 @@ tetrahedron22 c =
 
 tetrahedron23 :: Cube -> Tetrahedron
 tetrahedron23 c =
-    Tetrahedron fv' v0' v1' v2' v3'
+    make_tetrahedron c v0' v1' v2' v3'
     where
       v0' = center c
       v1' = center (left_face c)
@@ -447,8 +474,8 @@ tetrahedron23 c =
                        $ Tetrahedron.fv (tetrahedron0 c)
 
 
-tetrahedrons :: Cube -> [Tetrahedron]
-tetrahedrons c =
+tetrahedra :: Cube -> [Tetrahedron]
+tetrahedra c =
     [tetrahedron0 c,
      tetrahedron1 c,
      tetrahedron2 c,
@@ -474,12 +501,145 @@ tetrahedrons c =
      tetrahedron22 c,
      tetrahedron23 c]
 
-
--- | Takes a 'Cube', and returns all Tetrahedra belonging to it that
---   contain the given 'Point'.
-find_containing_tetrahedra :: Cube -> Point -> [Tetrahedron]
-find_containing_tetrahedra c p =
-    filter contains_our_point all_tetrahedra
-    where
-      contains_our_point = flip contains_point p
-      all_tetrahedra = tetrahedrons c
+-- | All completely contained in the front half of the cube.
+front_half_tetrahedra :: Cube -> [Tetrahedron]
+front_half_tetrahedra c =
+  [tetrahedron0 c,
+   tetrahedron1 c,
+   tetrahedron2 c,
+   tetrahedron3 c,
+   tetrahedron6 c,
+   tetrahedron12 c,
+   tetrahedron19 c,
+   tetrahedron21 c]
+
+
+-- | All tetrahedra completely contained in the top half of the cube.
+top_half_tetrahedra :: Cube -> [Tetrahedron]
+top_half_tetrahedra c =
+  [tetrahedron4 c,
+   tetrahedron5 c,
+   tetrahedron6 c,
+   tetrahedron7 c,
+   tetrahedron0 c,
+   tetrahedron10 c,
+   tetrahedron16 c,
+   tetrahedron20 c]
+
+
+-- | All tetrahedra completely contained in the back half of the cube.
+back_half_tetrahedra :: Cube -> [Tetrahedron]
+back_half_tetrahedra c =
+  [tetrahedron8 c,
+   tetrahedron9 c,
+   tetrahedron10 c,
+   tetrahedron11 c,
+   tetrahedron4 c,
+   tetrahedron14 c,
+   tetrahedron17 c,
+   tetrahedron23 c]
+
+
+-- | All tetrahedra completely contained in the down half of the cube.
+down_half_tetrahedra :: Cube -> [Tetrahedron]
+down_half_tetrahedra c =
+  [tetrahedron12 c,
+   tetrahedron13 c,
+   tetrahedron14 c,
+   tetrahedron15 c,
+   tetrahedron2 c,
+   tetrahedron8 c,
+   tetrahedron18 c,
+   tetrahedron22 c]
+
+
+-- | All tetrahedra completely contained in the right half of the cube.
+right_half_tetrahedra :: Cube -> [Tetrahedron]
+right_half_tetrahedra c =
+  [tetrahedron16 c,
+   tetrahedron17 c,
+   tetrahedron18 c,
+   tetrahedron19 c,
+   tetrahedron1 c,
+   tetrahedron5 c,
+   tetrahedron9 c,
+   tetrahedron13 c]
+
+
+-- | All tetrahedra completely contained in the left half of the cube.
+left_half_tetrahedra :: Cube -> [Tetrahedron]
+left_half_tetrahedra c =
+  [tetrahedron20 c,
+   tetrahedron21 c,
+   tetrahedron22 c,
+   tetrahedron23 c,
+   tetrahedron3 c,
+   tetrahedron7 c,
+   tetrahedron11 c,
+   tetrahedron15 c]
+
+
+in_top_half :: Cube -> Point -> Bool
+in_top_half c (_,_,z) =
+  distance_from_top <= distance_from_bottom
+  where
+    distance_from_top = abs $ (zmax c) - z
+    distance_from_bottom = abs $ (zmin c) - z
+
+in_front_half :: Cube -> Point -> Bool
+in_front_half c (x,_,_) =
+    distance_from_front <= distance_from_back
+  where
+    distance_from_front = abs $ (xmin c) - x
+    distance_from_back = abs $ (xmax c) - x
+
+
+in_left_half :: Cube -> Point -> Bool
+in_left_half c (_,y,_) =
+    distance_from_left <= distance_from_right
+  where
+    distance_from_left = abs $ (ymin c) - y
+    distance_from_right = abs $ (ymax c) - y
+
+
+-- | Takes a 'Cube', and returns the Tetrahedra belonging to it that
+--   contain the given 'Point'. This should be faster than checking
+--   every tetrahedron individually, since we determine which half
+--   (hemisphere?) of the cube the point lies in three times: once in
+--   each dimension. This allows us to eliminate non-candidates
+--   quickly.
+--
+--   This can throw an exception, but the use of 'head' might
+--   save us some unnecessary computations.
+--
+find_containing_tetrahedron :: Cube -> Point -> Tetrahedron
+find_containing_tetrahedron c p =
+  head containing_tetrahedra
+  where
+    candidates = tetrahedra c
+    non_candidates_x =
+        if (in_front_half c p) then
+          back_half_tetrahedra c
+        else
+          front_half_tetrahedra c
+
+    candidates_x = candidates \\ non_candidates_x
+
+    non_candidates_y =
+      if (in_left_half c p) then
+        right_half_tetrahedra c
+      else
+        left_half_tetrahedra c
+
+    candidates_xy = candidates_x \\ non_candidates_y
+
+    non_candidates_z =
+      if (in_top_half c p) then
+        down_half_tetrahedra c
+      else
+        top_half_tetrahedra c
+
+    candidates_xyz = candidates_xy \\ non_candidates_z
+
+    contains_our_point = flip contains_point p
+    containing_tetrahedra = filter contains_our_point candidates_xyz