Geometry Operations Enhancement (#122)

* updating exclusion domain
- update sample/ is_inside
- create tests

* difference fixes
- random iteration list for sample

* created Intersection

* created a Difference domain

* unittest

* docstrings and minor fixes

* Refacotring Geometries
- added OperationInterface
- redid test cases
- edited Union, Intersect, Exclusion, and Difference
to inherit from OperationInterface
- simplified Union, Intersect, Exclusion, and Difference

* rm lighting logs

---------

Co-authored-by: Dario Coscia <dariocoscia@cli-10-110-16-239.WIFIeduroamSTUD.units.it>

pina/geometry/operation_interface.py

@@ -0,0 +1,53 @@
+import torch
+from .location import Location
+from ..utils import check_consistency
+from ..label_tensor import LabelTensor
+from abc import ABCMeta, abstractmethod
+import random
+
+
+class OperationInterface(Location, metaclass=ABCMeta):
+    def __init__(self, geometries):
+        """
+        Abstract Operation class.
+        Any geometry operation entity must inherit from this class.
+
+        :param list geometries: A list of geometries from 'pina.geometry' 
+            such as 'EllipsoidDomain' or 'CartesianDomain'.
+        """
+        # check consistency geometries
+        check_consistency(geometries, Location)
+
+        # check we are passing always different 
+        # geometries with the same labels.
+        self._check_dimensions(geometries)
+        
+        # assign geometries
+        self._geometries = geometries
+
+    @property
+    def geometries(self):
+        """ 
+        The geometries."""
+        return self._geometries
+
+    @property
+    def variables(self):
+        """
+        Spatial variables.
+
+        :return: All the variables defined in ``__init__`` in order.
+        :rtype: list[str]
+        """
+        return self.geometries[0].variables
+
+    def _check_dimensions(self, geometries):
+        """Check if the dimensions of the geometries are consistent.
+
+        :param geometries: Geometries to be checked.
+        :type geometries: list[Location]
+        """
+        for geometry in geometries:
+            if geometry.variables != geometries[0].variables:
+                raise NotImplementedError(
+                    f'The geometries need to have same dimensions and labels.')