From: Michael Orlitzky <michael@orlitzky.com>
Date: Mon, 31 Oct 2011 04:56:14 +0000 (-0400)
Subject: Remove all "otherwise -> error" cases for performance reasons.
X-Git-Tag: 0.0.1~72
X-Git-Url: http://gitweb.michael.orlitzky.com/?p=spline3.git;a=commitdiff_plain;h=1bf996325008f79215a607d765adb042026f7444

Remove all "otherwise -> error" cases for performance reasons.
---

diff --git a/src/Cube.hs b/src/Cube.hs
index 11762a5..9f93143 100644
--- a/src/Cube.hs
+++ b/src/Cube.hs
@@ -506,9 +506,6 @@ tetrahedron cube 23 =
                        $ fv cube
       vol = tetrahedra_volume cube
 
--- Feels dirty, but whatever.
-tetrahedron _ _ = error "asked for a nonexistent tetrahedron"
-
 
 -- Only used in tests, so we don't need the added speed
 -- of Data.Vector.
diff --git a/src/FunctionValues.hs b/src/FunctionValues.hs
index 6d98e95..9c789f3 100644
--- a/src/FunctionValues.hs
+++ b/src/FunctionValues.hs
@@ -250,14 +250,6 @@ value_at v3d !i !j !k
           2*(value_at v3d i j 0) - (value_at v3d i j 1)
         else
           2*(value_at v3d i j (k-1)) - (value_at v3d i j (k-2))
-
-  | otherwise =
-      let istr = show i
-          jstr = show j
-          kstr = show k
-          coordstr = "(" ++ istr ++ "," ++ jstr ++ "," ++ kstr ++ ")"
-      in
-        error $ "value_at called outside of domain: " ++ coordstr
   where
     (dim_i, dim_j, dim_k) = dims v3d
 
diff --git a/src/Grid.hs b/src/Grid.hs
index dc52482..a1058d0 100644
--- a/src/Grid.hs
+++ b/src/Grid.hs
@@ -53,33 +53,27 @@ instance Arbitrary Grid where
       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.
+-- | The constructor that we want people to use.
+--   Ignore non-positive grid sizes for performance.
 make_grid :: Double -> Values3D -> Grid
-make_grid grid_size values
-    | grid_size <= 0 = error "grid size must be positive"
-    | otherwise = Grid grid_size values
+make_grid grid_size values =
+  Grid grid_size values
 
 
 
 -- | Takes a grid and a position as an argument and returns the cube
---   centered on that position. If there is no cube there (i.e. the
---   position is outside of the grid), it will throw an error.
+--   centered on that position. If there is no cube there, well, you
+--   shouldn't have done that. The omitted "otherwise" case actually
+--   does improve performance.
 cube_at :: Grid -> Int -> Int -> Int -> Cube
-cube_at !g !i !j !k
-    | i < 0      = error "i < 0 in cube_at"
-    | i >= xsize = error "i >= xsize in cube_at"
-    | j < 0      = error "j < 0 in cube_at"
-    | j >= ysize = error "j >= ysize in cube_at"
-    | k < 0      = error "k < 0 in cube_at"
-    | k >= zsize = error "k >= zsize in cube_at"
-    | otherwise = Cube delta i j k fvs' tet_vol
-      where
-        fvs = function_values g
-        (xsize, ysize, zsize) = dims fvs
-        fvs' = make_values fvs i j k
-        delta = h g
-        tet_vol = (1/24)*(delta^(3::Int))
+cube_at !g !i !j !k =
+   Cube delta i j k fvs' tet_vol
+   where
+     fvs = function_values g
+     fvs' = make_values fvs i j k
+     delta = h g
+     tet_vol = (1/24)*(delta^(3::Int))
+
 
 --   The first cube along any axis covers (-h/2, h/2). The second
 --   covers (h/2, 3h/2).  The third, (3h/2, 5h/2), and so on.
diff --git a/src/Misc.hs b/src/Misc.hs
index b9322ef..d0eb728 100644
--- a/src/Misc.hs
+++ b/src/Misc.hs
@@ -25,12 +25,12 @@ import Test.QuickCheck
 --   24
 --
 factorial :: Int -> Int
-factorial !n
-    | n > 20    = error "integer overflow in factorial function"
-    | otherwise = go 1 n
-    where go !acc !i
-                | i <= 1    = acc
-                | otherwise = go (acc * i) (i - 1)
+factorial !n =
+  go 1 n
+  where
+    go !acc !i
+      | i <= 1    = acc
+      | otherwise = go (acc * i) (i - 1)
 
 -- | Takes a three-dimensional list, and flattens it into a
 --   one-dimensional one.
diff --git a/src/Tetrahedron.hs b/src/Tetrahedron.hs
index 0ea0ffb..a6d69a2 100644
--- a/src/Tetrahedron.hs
+++ b/src/Tetrahedron.hs
@@ -125,10 +125,8 @@ polynomial t =
 -- | The Bernstein polynomial on t with indices i,j,k,l. Denoted by a
 --   capital 'B' in the Sorokina/Zeilfelder paper.
 beta :: Tetrahedron -> Int -> Int -> Int -> Int -> (RealFunction Point)
-beta t i j k l
-  | (i + j + k + l == 3) =
-      coefficient `cmult` (b0_term * b1_term * b2_term * b3_term)
-  | otherwise = error "basis function index out of bounds"
+beta t i j k l =
+  coefficient `cmult` (b0_term * b1_term * b2_term * b3_term)
   where
     denominator = (factorial i)*(factorial j)*(factorial k)*(factorial l)
     coefficient = 6 / (fromIntegral denominator)
@@ -141,8 +139,8 @@ beta t i j k l
 -- | The coefficient function. c t i j k l returns the coefficient
 --   c_ijkl with respect to the tetrahedron t. The definition uses
 --   pattern matching to mimic the definitions given in Sorokina and
---   Zeilfelder, pp. 84-86. If incorrect indices are supplied, the
---   function will simply error.
+--   Zeilfelder, pp. 84-86. If incorrect indices are supplied, the world
+--   will end. This is for performance reasons.
 c :: Tetrahedron -> Int -> Int -> Int -> Int -> Double
 c !t !i !j !k !l =
   coefficient i j k l
@@ -271,8 +269,6 @@ c !t !i !j !k !l =
                + (1/96)*(lt + fl + ft + rt + bt + fr)
                + (1/96)*(fd + ld + bd + br + rd + bl)
 
-    coefficient _ _ _ _ = error "coefficient index out of bounds"
-
 
 
 -- | Compute the determinant of the 4x4 matrix,
@@ -646,9 +642,8 @@ p78_24_properties =
   where
     -- | Returns the domain point of t with indices i,j,k,l.
     domain_point :: Tetrahedron -> Int -> Int -> Int -> Int -> Point
-    domain_point t i j k l
-      | i + j + k + l == 3 = weighted_sum `scale` (1/3)
-      | otherwise = error "domain point index out of bounds"
+    domain_point t i j k l =
+      weighted_sum `scale` (1/3)
       where
         v0' = (v0 t) `scale` (fromIntegral i)
         v1' = (v1 t) `scale` (fromIntegral j)