union domain implementation (#109)

* Union Class
* Implemented Union Tests

---------

Co-authored-by: Dario Coscia <93731561+dario-coscia@users.noreply.github.com>

tests/test_union.py

@@ -0,0 +1,46 @@
+import torch
+
+from pina import LabelTensor
+from pina.geometry import Union, EllipsoidDomain, CartesianDomain
+
+
+def test_constructor_two_CartesianDomains():
+    Union([CartesianDomain({'x': [0, 1], 'y': [0, 1]}),
+           CartesianDomain({'x': [0.5, 2], 'y': [-1, 0.1]})])
+
+
+def test_constructor_two_EllipsoidDomains():
+    Union([EllipsoidDomain({'x': [-1, 1], 'y': [-1, 1], 'z': [-1, 1]}),
+           EllipsoidDomain({'x': [-0.5, 0.5], 'y': [-0.5, 0.5], 'z': [-0.5, 0.5]})])
+
+
+def test_constructor_EllipsoidDomain_CartesianDomain():
+    Union([EllipsoidDomain({'x': [-1, 1], 'y': [-1, 1]}),
+           CartesianDomain({'x': [-0.5, 0.5], 'y': [-0.5, 0.5]})])
+
+
+def test_is_inside_two_CartesianDomains():
+    pt_1 = LabelTensor(torch.tensor([[0.5, 0.5]]), ['x', 'y'])
+    pt_2 = LabelTensor(torch.tensor([[-1, -1]]), ['x', 'y'])
+    domain = Union([CartesianDomain({'x': [0, 1], 'y': [0, 1]}),
+                    CartesianDomain({'x': [0.5, 2], 'y': [-1, 0.1]})])
+    assert domain.is_inside(pt_1) == True
+    assert domain.is_inside(pt_2) == False
+
+
+def test_is_inside_two_EllipsoidDomains():
+    pt_1 = LabelTensor(torch.tensor([[0.5, 0.5, 0.5]]), ['x', 'y', 'z'])
+    pt_2 = LabelTensor(torch.tensor([[-1, -1, -1]]), ['x', 'y', 'z'])
+    domain = Union([EllipsoidDomain({'x': [-1, 1], 'y': [-1, 1], 'z': [-1, 1]}),
+                    EllipsoidDomain({'x': [-0.5, 0.5], 'y': [-0.5, 0.5], 'z': [-0.5, 0.5]})])
+    assert domain.is_inside(pt_1) == True
+    assert domain.is_inside(pt_2) == False
+
+
+def test_is_inside_EllipsoidDomain_CartesianDomain():
+    pt_1 = LabelTensor(torch.tensor([[0.5, 0.5]]), ['x', 'y'])
+    pt_2 = LabelTensor(torch.tensor([[-1, -1]]), ['x', 'y'])
+    domain = Union([EllipsoidDomain({'x': [-1, 1], 'y': [-1, 1], }),
+                    CartesianDomain({'x': [0.6, 1.5], 'y': [-2, 0]})])
+    assert domain.is_inside(pt_1) == True
+    assert domain.is_inside(pt_2) == False