+
+
+
+
+-- | Check the volume of a particular tetrahedron (computed by hand)
+-- Its vertices are in clockwise order, so the volume should be
+-- negative.
+tetrahedron1_geometry_tests :: TestTree
+tetrahedron1_geometry_tests =
+ testGroup "tetrahedron1 geometry"
+ [ testCase "volume1" volume1 ]
+ where
+ p0 = Point 0 (-0.5) 0
+ p1 = Point 0 0.5 0
+ p2 = Point 2 0 0
+ p3 = Point 1 0 1
+ t = Tetrahedron { v0 = p0,
+ v1 = p1,
+ v2 = p2,
+ v3 = p3,
+ function_values = empty_values,
+ precomputed_volume = 0 }
+
+ volume1 :: Assertion
+ volume1 =
+ assertEqual "volume is correct" True (vol ~= (-1/3))
+ where
+ vol = volume t
+
+
+-- | Check the volume of a particular tetrahedron (computed by hand)
+-- Its vertices are in counter-clockwise order, so the volume should
+-- be positive.
+tetrahedron2_geometry_tests :: TestTree
+tetrahedron2_geometry_tests =
+ testGroup "tetrahedron2 geometry"
+ [ testCase "volume1" volume1 ]
+ where
+ p0 = Point 0 (-0.5) 0
+ p1 = Point 2 0 0
+ p2 = Point 0 0.5 0
+ p3 = Point 1 0 1
+ t = Tetrahedron { v0 = p0,
+ v1 = p1,
+ v2 = p2,
+ v3 = p3,
+ function_values = empty_values,
+ precomputed_volume = 0 }
+
+ volume1 :: Assertion
+ volume1 = assertEqual "volume1 is correct" True (vol ~= (1/3))
+ where
+ vol = volume t
+
+
+
+-- | The barycentric coordinate of v0 with respect to itself should
+-- be one.
+prop_b0_v0_always_unity :: Tetrahedron -> Property
+prop_b0_v0_always_unity t =
+ (volume t) > 0 ==> (b0 t) (v0 t) ~= 1.0
+
+-- | The barycentric coordinate of v1 with respect to v0 should
+-- be zero.
+prop_b0_v1_always_zero :: Tetrahedron -> Property
+prop_b0_v1_always_zero t =
+ (volume t) > 0 ==> (b0 t) (v1 t) ~= 0
+
+-- | The barycentric coordinate of v2 with respect to v0 should
+-- be zero.
+prop_b0_v2_always_zero :: Tetrahedron -> Property
+prop_b0_v2_always_zero t =
+ (volume t) > 0 ==> (b0 t) (v2 t) ~= 0
+
+-- | The barycentric coordinate of v3 with respect to v0 should
+-- be zero.
+prop_b0_v3_always_zero :: Tetrahedron -> Property
+prop_b0_v3_always_zero t =
+ (volume t) > 0 ==> (b0 t) (v3 t) ~= 0
+
+-- | The barycentric coordinate of v1 with respect to itself should
+-- be one.
+prop_b1_v1_always_unity :: Tetrahedron -> Property
+prop_b1_v1_always_unity t =
+ (volume t) > 0 ==> (b1 t) (v1 t) ~= 1.0
+
+-- | The barycentric coordinate of v0 with respect to v1 should
+-- be zero.
+prop_b1_v0_always_zero :: Tetrahedron -> Property
+prop_b1_v0_always_zero t =
+ (volume t) > 0 ==> (b1 t) (v0 t) ~= 0
+
+-- | The barycentric coordinate of v2 with respect to v1 should
+-- be zero.
+prop_b1_v2_always_zero :: Tetrahedron -> Property
+prop_b1_v2_always_zero t =
+ (volume t) > 0 ==> (b1 t) (v2 t) ~= 0
+
+-- | The barycentric coordinate of v3 with respect to v1 should
+-- be zero.
+prop_b1_v3_always_zero :: Tetrahedron -> Property
+prop_b1_v3_always_zero t =
+ (volume t) > 0 ==> (b1 t) (v3 t) ~= 0
+
+-- | The barycentric coordinate of v2 with respect to itself should
+-- be one.
+prop_b2_v2_always_unity :: Tetrahedron -> Property
+prop_b2_v2_always_unity t =
+ (volume t) > 0 ==> (b2 t) (v2 t) ~= 1.0
+
+-- | The barycentric coordinate of v0 with respect to v2 should
+-- be zero.
+prop_b2_v0_always_zero :: Tetrahedron -> Property
+prop_b2_v0_always_zero t =
+ (volume t) > 0 ==> (b2 t) (v0 t) ~= 0
+
+-- | The barycentric coordinate of v1 with respect to v2 should
+-- be zero.
+prop_b2_v1_always_zero :: Tetrahedron -> Property
+prop_b2_v1_always_zero t =
+ (volume t) > 0 ==> (b2 t) (v1 t) ~= 0
+
+-- | The barycentric coordinate of v3 with respect to v2 should
+-- be zero.
+prop_b2_v3_always_zero :: Tetrahedron -> Property
+prop_b2_v3_always_zero t =
+ (volume t) > 0 ==> (b2 t) (v3 t) ~= 0
+
+-- | The barycentric coordinate of v3 with respect to itself should
+-- be one.
+prop_b3_v3_always_unity :: Tetrahedron -> Property
+prop_b3_v3_always_unity t =
+ (volume t) > 0 ==> (b3 t) (v3 t) ~= 1.0
+
+-- | The barycentric coordinate of v0 with respect to v3 should
+-- be zero.
+prop_b3_v0_always_zero :: Tetrahedron -> Property
+prop_b3_v0_always_zero t =
+ (volume t) > 0 ==> (b3 t) (v0 t) ~= 0
+
+-- | The barycentric coordinate of v1 with respect to v3 should
+-- be zero.
+prop_b3_v1_always_zero :: Tetrahedron -> Property
+prop_b3_v1_always_zero t =
+ (volume t) > 0 ==> (b3 t) (v1 t) ~= 0
+
+-- | The barycentric coordinate of v2 with respect to v3 should
+-- be zero.
+prop_b3_v2_always_zero :: Tetrahedron -> Property
+prop_b3_v2_always_zero t =
+ (volume t) > 0 ==> (b3 t) (v2 t) ~= 0
+
+
+prop_swapping_vertices_doesnt_affect_coefficients1 :: Tetrahedron -> Bool
+prop_swapping_vertices_doesnt_affect_coefficients1 t =
+ c t 0 0 1 2 == c t' 0 0 1 2
+ where
+ t' = t { v0 = (v1 t), v1 = (v0 t) }
+
+prop_swapping_vertices_doesnt_affect_coefficients2 :: Tetrahedron -> Bool
+prop_swapping_vertices_doesnt_affect_coefficients2 t =
+ c t 0 1 1 1 == c t' 0 1 1 1
+ where
+ t' = t { v2 = (v3 t), v3 = (v2 t) }
+
+prop_swapping_vertices_doesnt_affect_coefficients3 :: Tetrahedron -> Bool
+prop_swapping_vertices_doesnt_affect_coefficients3 t =
+ c t 2 1 0 0 == c t' 2 1 0 0
+ where
+ t' = t { v2 = (v3 t), v3 = (v2 t) }
+
+prop_swapping_vertices_doesnt_affect_coefficients4 :: Tetrahedron -> Bool
+prop_swapping_vertices_doesnt_affect_coefficients4 t =
+ c t 2 0 0 1 == c t' 2 0 0 1
+ where
+ t' = t { v0 = (v3 t), v3 = (v0 t) }
+
+
+
+
+tetrahedron_tests :: TestTree
+tetrahedron_tests =
+ testGroup "Tetrahedron tests" [
+ tetrahedron1_geometry_tests,
+ tetrahedron2_geometry_tests ]
+
+
+
+p78_24_properties :: TestTree
+p78_24_properties =
+ testGroup "p. 78, Section (2.4) properties" [
+ testProperty "c3000 identity" prop_c3000_identity,
+ testProperty "c2100 identity" prop_c2100_identity,
+ testProperty "c1110 identity" prop_c1110_identity]
+ 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 =
+ weighted_sum `scale` (1/3)
+ where
+ v0' = (v0 t) `scale` (fromIntegral i)
+ v1' = (v1 t) `scale` (fromIntegral j)
+ v2' = (v2 t) `scale` (fromIntegral k)
+ v3' = (v3 t) `scale` (fromIntegral l)
+ weighted_sum = v0' + v1' + v2' + v3'
+
+
+ -- | Used for convenience in the next few tests.
+ p :: Tetrahedron -> Int -> Int -> Int -> Int -> Double
+ p t i j k l = (polynomial t) (domain_point t i j k l)
+
+
+ -- | Given in Sorokina and Zeilfelder, p. 78.
+ prop_c3000_identity :: Tetrahedron -> Property
+ prop_c3000_identity t =
+ (volume t) > 0 ==>
+ c t 3 0 0 0 ~= p t 3 0 0 0
+
+ -- | Given in Sorokina and Zeilfelder, p. 78.
+ prop_c2100_identity :: Tetrahedron -> Property
+ prop_c2100_identity t =
+ (volume t) > 0 ==>
+ c t 2 1 0 0 ~= (term1 - term2 + term3 - term4)
+ where
+ term1 = (1/3)*(p t 0 3 0 0)
+ term2 = (5/6)*(p t 3 0 0 0)
+ term3 = 3*(p t 2 1 0 0)
+ term4 = (3/2)*(p t 1 2 0 0)
+
+ -- | Given in Sorokina and Zeilfelder, p. 78.
+ prop_c1110_identity :: Tetrahedron -> Property
+ prop_c1110_identity t =
+ (volume t) > 0 ==>
+ c t 1 1 1 0 ~= (term1 + term2 - term3 - term4)
+ where
+ term1 = (1/3)*((p t 3 0 0 0) + (p t 0 3 0 0) + (p t 0 0 3 0))
+ term2 = (9/2)*(p t 1 1 1 0)
+ term3 = (3/4)*((p t 2 1 0 0) + (p t 1 2 0 0) + (p t 2 0 1 0))
+ term4 = (3/4)*((p t 1 0 2 0) + (p t 0 2 1 0) + (p t 0 1 2 0))
+
+
+
+tetrahedron_properties :: TestTree
+tetrahedron_properties =
+ testGroup "Tetrahedron properties" [
+ p78_24_properties,
+ testProperty "b0_v0_always_unity" prop_b0_v0_always_unity,
+ testProperty "b0_v1_always_zero" prop_b0_v1_always_zero,
+ testProperty "b0_v2_always_zero" prop_b0_v2_always_zero,
+ testProperty "b0_v3_always_zero" prop_b0_v3_always_zero,
+ testProperty "b1_v1_always_unity" prop_b1_v1_always_unity,
+ testProperty "b1_v0_always_zero" prop_b1_v0_always_zero,
+ testProperty "b1_v2_always_zero" prop_b1_v2_always_zero,
+ testProperty "b1_v3_always_zero" prop_b1_v3_always_zero,
+ testProperty "b2_v2_always_unity" prop_b2_v2_always_unity,
+ testProperty "b2_v0_always_zero" prop_b2_v0_always_zero,
+ testProperty "b2_v1_always_zero" prop_b2_v1_always_zero,
+ testProperty "b2_v3_always_zero" prop_b2_v3_always_zero,
+ testProperty "b3_v3_always_unity" prop_b3_v3_always_unity,
+ testProperty "b3_v0_always_zero" prop_b3_v0_always_zero,
+ testProperty "b3_v1_always_zero" prop_b3_v1_always_zero,
+ testProperty "b3_v2_always_zero" prop_b3_v2_always_zero,
+ testProperty "swapping_vertices_doesnt_affect_coefficients1"
+ prop_swapping_vertices_doesnt_affect_coefficients1,
+ testProperty "swapping_vertices_doesnt_affect_coefficients2"
+ prop_swapping_vertices_doesnt_affect_coefficients2,
+ testProperty "swapping_vertices_doesnt_affect_coefficients3"
+ prop_swapping_vertices_doesnt_affect_coefficients3,
+ testProperty "swapping_vertices_doesnt_affect_coefficients4"
+ prop_swapping_vertices_doesnt_affect_coefficients4 ]