Implement Dataset, Dataloader and DataModule class and fix SupervisedSolver

pina/data/pina_subset.py

@@ -0,0 +1,21 @@
+class PinaSubset:
+    """
+    TODO
+    """
+    __slots__ = ['dataset', 'indices']
+
+    def __init__(self, dataset, indices):
+        """
+        TODO
+        """
+        self.dataset = dataset
+        self.indices = indices
+
+    def __len__(self):
+        """
+        TODO
+        """
+        return len(self.indices)
+
+    def __getattr__(self, name):
+        return self.dataset.__getattribute__(name)