add helper method .dimensionless (#43)

Author: NoureldinYosri

test/test_value.py

@@ -29,7 +29,7 @@ def test_construction() -> None:
     assert isinstance(3j * x, Value)
 
 
-def test_dimensionless() -> None:
+def test_dimensionless_act_like_float() -> None:
     """Test that dimensionless values act like floats"""
     x = Value(1.5, '')
     y = Value(1.5, 'us/ns')
@@ -254,3 +254,12 @@ def test_sign() -> None:
     for x in np.linspace(-10, 10, 20):
         v = Value(x, 'ns')
         assert v.sign() == np.sign(x)
+
+
+def test_dimensionless() -> None:
+    A, B = Value(1, 'GHz^2'), Value(1200, 'MHz/GHz')
+
+    with pytest.raises(ValueError):
+        _ = A.dimensionless()
+
+    assert B.dimensionless() == 1.2

test/test_value_array.py

@@ -82,6 +82,14 @@ def test_power() -> None:
     assert np.array_equal((s * [1, 2, 3]) ** 2, s * s * [1, 4, 9])
 
 
+def test_dimensionless_act_like_arrays() -> None:
+    x = ValueArray(1.5 * np.arange(5), '')
+    y = ValueArray(1.5 * np.arange(5), 'us/ns')
+
+    np.testing.assert_allclose(np.sqrt(x), np.sqrt(1.5 * np.arange(5)))
+    np.testing.assert_allclose(np.sin(y), np.sin(1.5 * np.arange(5) * 1000))
+
+
 def test_repr() -> None:
     from tunits.units import km, kg, s
 
@@ -206,18 +214,27 @@ def test_divison_with_dimensionless_preserves_ratios() -> None:
 
 
 def test_units() -> None:
-    A, B = Value(np.random.random(10), 'GHz^2'), Value(np.random.random(10), 'MHz/GHz')
+    A, B = ValueArray(np.random.random(10), 'GHz^2'), ValueArray(np.random.random(10), 'MHz/GHz')
     assert A.units == 'GHz^2'
     assert B.units == 'MHz/GHz'
 
 
 def test_base_unit() -> None:
-    A, B = Value(np.random.random(10), 'GHz^2'), Value(np.random.random(10), 'MHz/GHz')
+    A, B = ValueArray(np.random.random(10), 'GHz^2'), ValueArray(np.random.random(10), 'MHz/GHz')
     assert A.base_unit == Value(1, 'Hz^2')
     assert B.base_unit == Value(1, '')
 
 
 def test_sign() -> None:
     for x in np.random.random((10, 3, 4)):
-        v = Value(x, 'ns')
+        v = ValueArray(x, 'ns')
         np.testing.assert_equal(v.sign(), np.sign(x))
+
+
+def test_dimensionless() -> None:
+    A, B = ValueArray([1, 2, 3], 'GHz^2'), ValueArray(np.arange(5), 'MHz/GHz')
+
+    with pytest.raises(ValueError):
+        _ = A.dimensionless()
+
+    np.testing.assert_equal(B.dimensionless(), np.arange(5) / 1000)

tunits/core/__init__.pyi

@@ -317,6 +317,7 @@ class Value(Generic[NumericalT], WithUnit, np.generic, SupportsIndex):
     def __index__(self) -> int: ...
     def __pow__(self, other: Any, modulus: Any = None) -> Value: ...
     def sign(self) -> int: ...
+    def dimensionless(self) -> float: ...
 
 class ValueArray(Generic[ValueType2], WithUnit):
     value: NDArray[Any]
@@ -378,6 +379,7 @@ class ValueArray(Generic[ValueType2], WithUnit):
     ) -> ValueArray: ...
     def __pow__(self, other: Any, modulus: Any = None) -> ValueArray: ...
     def sign(self) -> NDArray[np.integer]: ...
+    def dimensionless(self) -> NDArray[Any]: ...
 
 def init_base_unit_functions(
     try_interpret_as_with_unit: Callable[[Any, bool], WithUnit | None],

tunits/core/cython/with_unit.pyx

@@ -669,6 +669,11 @@ cdef class WithUnit:
     def sign(self) -> int | np.ndarray:
         return np.sign(self.value_in_base_units())
 
+    def dimensionless(self) -> float | np.ndarray:
+        if not self._is_dimensionless():
+            raise ValueError(f'{self} is not dimensionless')
+        return self.value_in_base_units()
+
 _try_interpret_as_with_unit = None
 _is_value_consistent_with_default_unit_database = None
 def init_base_unit_functions(

tunits/core/cython/with_unit_value_array.pyx

@@ -144,6 +144,9 @@ class ValueArray(WithUnit):
         ]:
             return getattr(ufunc, method)(*(np.asarray(x) for x in inputs), **kwargs)
 
+        if self._is_dimensionless():
+            return getattr(ufunc, method)(*(np.asarray(x) for x in inputs), **kwargs)
+
         raise NotImplemented
 
     @property