add Angle dimension

evalf · Sep 29, 2022 · 23f287e · 23f287e
1 parent 1ba224b
commit 23f287e
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Showing 2 changed files with 40 additions and 2 deletions.
diff --git a/nutils/SI.py b/nutils/SI.py
@@ -202,6 +202,18 @@ def _dispatch(op, *args, **kwargs):
             args = [q.__value for q in stack_args],
         elif name in ('shape', 'ndim', 'size', 'sign'):
             Dim = None
+        elif name in ('sin', 'cos', 'tan'):
+            if not isinstance(args[0], Angle):
+                raise TypeError(f'trigonometric functions require angle [Φ], got {type(args[0]).__name__}')
+            Dim = Dimensionless
+        elif name in ('arcsin', 'arccos', 'arctan'):
+            if not isinstance(args[0], Dimensionless):
+                raise TypeError(f'inverse trigonometric functions require dimensionless [], got {type(args[0]).__name__}')
+            Dim = Angle
+        elif name == 'arctan2':
+            if type(args[0]) != type(args[1]):
+                raise TypeError(f'arguments of arctan2 must have equal dimension, got {type(args[0]).__name__} and {type(args[1]).__name__}')
+            Dim = Angle
         else:
             return NotImplemented
         try:
@@ -315,6 +327,7 @@ def _split_factors(s):
 Temperature = Dimension.create('θ')
 AmountOfSubstance = Dimension.create('N')
 LuminousFlux = LuminousIntensity = Dimension.create('J')
+Angle = Dimension.create('Φ')
 
 Area = Length**2
 Volume = Length**3
@@ -358,6 +371,7 @@ def _split_factors(s):
 units.K = Temperature(1.)
 units.mol = AmountOfSubstance(1.)
 units.cd = LuminousIntensity(1.)
+units.rad = Angle(1.)
 
 units.N = 'kg*m/s2' # newton
 units.Pa = 'N/m2' # pascal
@@ -388,3 +402,4 @@ def _split_factors(s):
 units.t = '1000kg' # ton
 units.Da = '1.66053904020yg' # dalton
 units.eV = '.1602176634aJ' # electronvolt
+units.deg = '0.017453292519943295rad' # degree
diff --git a/tests/test_SI.py b/tests/test_SI.py
@@ -44,10 +44,14 @@ def test_pickle(self):
 
 class Quantity(unittest.TestCase):
 
-    def assertWrapped(self, quantity, expect_dim, expect_val):
+    def assertWrapped(self, quantity, expect_dim, expect_val, tol=0):
         dim, val = quantity.__unwrap_quantity__()
         self.assertEqual(dim, expect_dim)
-        self.assertEqual(numpy.asarray(val).tolist(), numpy.asarray(expect_val).tolist())
+        if not tol:
+            self.assertEqual(numpy.asarray(val).tolist(), numpy.asarray(expect_val).tolist())
+        else:
+            self.assertEqual(numpy.shape(val), numpy.shape(expect_val))
+            self.assertTrue(numpy.allclose(val, expect_val, atol=tol))
 
     def test_fromstring(self):
         self.assertWrapped(SI.parse('5kN'), SI.Force, 5000)
@@ -258,3 +262,22 @@ def test_round(self):
         with self.assertRaises(ValueError):
             round(F)
         self.assertEqual(round(F / SI.units.N), 2)
+
+    def test_angle(self):
+        φ = SI.Angle('30deg')
+        self.assertWrapped(numpy.sin(φ), SI.Dimensionless, .5, tol=1e-10)
+        self.assertWrapped(numpy.cos(φ), SI.Dimensionless, numpy.sqrt(3)/2, tol=1e-10)
+        self.assertWrapped(numpy.tan(φ), SI.Dimensionless, 1/numpy.sqrt(3), tol=1e-10)
+        with self.assertRaisesRegex(TypeError, r'trigonometric functions require angle \[Φ\], got \[L\]'):
+            numpy.sin(SI.parse('2m'))
+        v = SI.Dimensionless(1.)
+        self.assertWrapped(numpy.arcsin(v), SI.Angle, numpy.pi/2, tol=1e-10)
+        self.assertWrapped(numpy.arccos(v), SI.Angle, 0, tol=1e-10)
+        self.assertWrapped(numpy.arctan(v), SI.Angle, numpy.pi/4, tol=1e-10)
+        with self.assertRaisesRegex(TypeError, r'inverse trigonometric functions require dimensionless \[\], got \[L\]'):
+            numpy.arcsin(SI.parse('2m'))
+        a = SI.Length('1m')
+        b = SI.Length('-1m')
+        self.assertWrapped(numpy.arctan2(a, b), SI.Angle, .75*numpy.pi, tol=1e-10)
+        with self.assertRaisesRegex(TypeError, r'arguments of arctan2 must have equal dimension, got \[L\] and \[M\]'):
+            numpy.arctan2(SI.parse('2m'), SI.parse('1kg'))