nngraph verifier & verifier for all rules (#10)

nas/graph/nn_graph_verifier.py

@@ -0,0 +1,41 @@
+from typing import Sequence, Union, Callable
+
+from fedot.core.dag.graph import Graph
+from fedot.core.log import default_log
+from fedot.core.optimisers.graph import OptGraph
+
+from nas.operations.validation_rules.cnn_val_rules import unique_node_types, flatten_count, has_no_flatten_skip, \
+    graph_has_several_starts, graph_has_wrong_structure
+
+
+# Validation rule can either return False or raise a ValueError to signal a failed check
+VerifierRuleType = Callable[..., bool]
+
+
+class NNGraphVerifier:
+    """ Class to verify graph using specified rules """
+    def __init__(self,
+                 rules: Sequence[VerifierRuleType] = ()):
+        self._rules = rules
+        self._log = default_log(self)
+
+    def __call__(self, graph: Union[Graph, OptGraph]) -> bool:
+        return self.verify(graph)
+
+    def verify(self, graph: Union[Graph, OptGraph]) -> bool:
+        # Check if all rules pass
+        for rule in self._rules:
+            try:
+                if rule(graph) is False:
+                    return False
+            except ValueError as err:
+                self._log.debug(f'Graph verification failed with error <{err}> '
+                                f'for rule={rule} on graph={graph.root_node.descriptive_id}.')
+                return False
+        return True
+
+
+def verifier_with_all_rules():
+    rules = [unique_node_types, flatten_count,
+             has_no_flatten_skip, graph_has_several_starts, graph_has_wrong_structure]
+    return NNGraphVerifier(rules=rules)