Initial Work on Reading Crystal and Creation Gaussian Input

crystalpol/shared/system/crystal.py

@@ -0,0 +1,43 @@
+from crystalpol.shared.system.molecule import Molecule
+
+from typing import List
+
+
+class Crystal:
+    """
+    This class represents a crystal, it will be organized in a list structure.
+    Each element is a unitary cell in the crystal. And this unitary cell will have
+    Molecules in it.
+    """
+
+    def __init__(self, structure: List[List[str]]):
+        self.structure = structure
+
+        self.cells = []
+
+    def __iter__(self):
+        for cell in self.cells:
+            yield cell
+
+    def __len__(self):
+        return len(self.cells)
+
+    def __getitem__(self, index):
+        return self.cells[index]
+
+    def add_cell(self, cell: List[Molecule]) -> None:
+        valid = self._is_valid_cell(cell)
+        if not valid:
+            raise ValueError(
+                "This cell does not obey the declared format for this Crystal."
+            )
+        else:
+            self.cells.append(cell)
+
+    def _is_valid_cell(self, cell: List[Molecule]) -> bool:
+        if len(cell) == len(self.structure):
+            for i, molecule in enumerate(cell):
+                if len(molecule.atoms) == len(self.structure[i]) \
+                        and all(atom.symbol == self.structure[i][j] for j, atom in enumerate(molecule.atoms)):
+                    return True
+        return False