feat: Vector multiplication

pyproject.toml

@@ -46,6 +46,8 @@ ignore = [
     "TCH003",  # same as TCH001
 
     "SIM103",  # less readable in some cases imo
+
+    "SLF001",  # necessary for vector operations
 ]
 
 [tool.mypy]

quantio/vector.py

@@ -4,6 +4,8 @@
 
 import numpy as np
 
+from ._quantity_base import _QuantityBase
+
 T = TypeVar("T")
 
 
@@ -38,6 +40,33 @@ def __sub__(self, other: Vector[T] | np.ndarray) -> Vector[T]:
         other_elements = other._elements if isinstance(other, Vector) else np.array(other)
         return Vector[T](self._elements - other_elements)
 
+    def __mul__(self, other: Vector | np.ndarray | float) -> np.ndarray:
+        """Multipy this vector with either another vector or a scalar."""
+        if isinstance(self._elements[0], _QuantityBase):
+            self_elements = np.array([element._base_value for element in self._elements])
+        else:
+            self_elements = self._elements
+
+        if isinstance(other, (float, int)):
+            other_elements = np.array([other])
+
+        elif isinstance(other, _QuantityBase):
+            other_elements = np.array([other._base_value])
+
+        elif isinstance(other, Vector):
+            if isinstance(self._elements[0], _QuantityBase):
+                other_elements = np.array([element._base_value for element in other._elements])
+            else:
+                other_elements = other._elements
+
+        elif isinstance(other, np.ndarray):
+            other_elements = other
+
+        else:
+            raise TypeError
+
+        return self_elements * other_elements
+
     def __eq__(self, other: object) -> bool:
         """Assess if this object is the same as another."""
         if not isinstance(other, Vector):

test/test_vector.py

@@ -59,5 +59,53 @@ def test_subtract__wrong_type():
         vec1 - vec2
 
 
+def test_multiply__with_vector_of_quantities():
+    vec1: Vector[Length] = Vector([Length(meters=1), Length(meters=2)])
+    vec2: Vector[Length] = Vector([Length(meters=3), Length(meters=4)])
+
+    actual = vec2 * vec1
+    assert np.all(actual == np.array([3, 8]))
+
+
+def test_multiply__with_vector_of_float():
+    vec1: Vector[float] = Vector([1, 2])
+    vec2: Vector[float] = Vector([3, 4])
+
+    actual = vec2 * vec1
+    assert np.all(actual == np.array([3, 8]))
+
+
+def test_multiply__with_array():
+    vec: Vector[Length] = Vector([Length(meters=1), Length(meters=2)])
+    array = np.array([3, 4])
+
+    actual = vec * array
+    assert np.all(actual == np.array([3, 8]))
+
+
+def test_multiply__with_scalar_float():
+    vec: Vector[Length] = Vector([Length(meters=1), Length(meters=2)])
+    scalar = 5
+
+    actual = vec * scalar
+    assert np.all(actual == np.array([5, 10]))
+
+
+def test_multiply__with_scalar_quantitiy():
+    vec: Vector[Length] = Vector([Length(meters=1), Length(meters=2)])
+    scalar = Length(meters=5)
+
+    actual = vec * scalar
+    assert np.all(actual == np.array([5, 10]))
+
+
+def test_multiply__wrong_dimension():
+    vec1: Vector[Length] = Vector([Length(meters=1), Length(meters=2), Length(meters=2)])
+    vec2: Vector[Length] = Vector([Length(meters=3), Length(meters=4)])
+
+    with pytest.raises(ValueError):
+        vec1 * vec2
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])