add Angle dimension

evalf · Sep 30, 2022 · a38f302 · a38f302
1 parent 28a0bef
commit a38f302
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Showing 2 changed files with 26 additions and 0 deletions.
diff --git a/nutils/SI.py b/nutils/SI.py
@@ -200,6 +200,14 @@ def _dispatch(op, *args, **kwargs):
             args = [q.__value for q in stack_args],
         elif name in ('shape', 'ndim', 'size', 'sign'):
             Dim = Dimension.from_powers({})
+        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 = Dimension.from_powers({})
+        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
         assert isinstance(Dim, Dimension)
@@ -312,6 +320,7 @@ def _split_factors(s):
 Temperature = Dimension.create('θ')
 AmountOfSubstance = Dimension.create('N')
 LuminousFlux = LuminousIntensity = Dimension.create('J')
+Angle = Dimension.create('A')
 
 Area = Length**2
 Volume = Length**3
@@ -355,6 +364,7 @@ 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
@@ -385,3 +395,4 @@ 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
@@ -252,3 +252,18 @@ def test_type_error(self):
         for F in SI.Force('2N'), numpy.array([1,2,3]) * SI.Force('N'):
             with self.assertRaisesRegex(TypeError, r"unsupported operand type\(s\) for /: '\[M\*L/T2\]' and 'object'"):
                 F / object()
+
+    def test_angle(self):
+        φ = SI.Angle('30deg')
+        self.assertTrue(numpy.isclose(numpy.sin(φ), .5))
+        self.assertTrue(numpy.isclose(numpy.cos(φ), numpy.sqrt(3)/2))
+        self.assertTrue(numpy.isclose(numpy.tan(φ), 1/numpy.sqrt(3)))
+        with self.assertRaisesRegex(TypeError, r'trigonometric functions require angle \[Φ\], got \[L\]'):
+            numpy.sin(SI.parse('2m'))
+        a = SI.Length('1m')
+        b = SI.Length('-1m')
+        dim, val = numpy.arctan2(a, b).__unwrap_quantity__()
+        self.assertEqual(dim, SI.Angle)
+        self.assertTrue(numpy.isclose(val, .75*numpy.pi))
+        with self.assertRaisesRegex(TypeError, r'arguments of arctan2 must have equal dimension, got \[L\] and \[M\]'):
+            numpy.arctan2(SI.parse('2m'), SI.parse('1kg'))