Add to_dict() and from_dict() to SupplyChainNetwork (part of #14)

src/stockpyl/supply_chain_network.py

@@ -266,9 +266,51 @@ def to_dict(self):
 		for n in self.nodes:
 			network_dict['nodes'].append(n.to_dict())
 
-		# TODO: need to replicate network structure
-
 		return network_dict
+
+	@classmethod
+	def from_dict(cls, the_dict):
+		"""Return a new |class_network| object with attributes copied from the
+		values in ``the_dict``. 
+
+		Parameters
+		----------
+		the_dict : dict
+			Dict representation of a |class_network|, typically created using ``to_dict()``.
+
+		Returns
+		-------
+		SupplyChainNetwork
+			The object converted from the dict.
+		"""
+		if the_dict is None:
+			network = None
+		else:
+			# Initialize node object.
+			network = SupplyChainNetwork()
+
+		# Non-object attributes.
+		network.period 						= the_dict['period']
+		network.max_max_replenishment_time	= the_dict['max_max_replenishment_time']
+
+		# Nodes.
+		for n_dict in the_dict['nodes']:
+			network.nodes.append(SupplyChainNode.from_dict(n_dict))
+
+		# Convert nodes' successors and predecessors back to node objects. (SupplyChainNode.to_dict()
+		# replaces them with indices.)
+		for n in network.nodes:
+			preds = []
+			succs = []
+			for m in network.nodes:
+				if m.index in n.predecessors():
+					preds.append(m)
+				if m.index in n.successors():
+					succs.append(m)
+			n._predecessors = preds
+			n._successors = succs
+
+		return network
 
 	# Methods for node handling.
 

tests/test_supply_chain_network.py

@@ -1707,3 +1707,101 @@ def test_example_6_1_renumbered(self):
 		S_echelon = {3: 10, 2: 15, 1: 5}
 		S_local = echelon_to_local_base_stock_levels(instance, S_echelon)
 		self.assertDictEqual(S_local, {3: 5, 2: 0, 1: 0})
+
+
+class TestToFromDict(unittest.TestCase):
+	@classmethod
+	def set_up_class(cls):
+		"""Called once, before any tests."""
+		print_status('TestToFromDict', 'set_up_class()')
+
+	@classmethod
+	def tear_down_class(cls):
+		"""Called once, after all tests, if set_up_class successful."""
+		print_status('TestToFromDict', 'tear_down_class()')
+
+	def test_example_6_1(self):
+		"""Test that to_dict() and from_dict() correctly convert SupplyChainNetwork object to and from dict
+		in Example 6.1.
+		"""
+		print_status('TestToFromDict', 'test_example_6_1()')
+
+		network = load_instance("example_6_1")
+
+		# Convert network to dict.
+		network_dict = network.to_dict()
+
+		# Convert dict back to network.
+		dict_network = SupplyChainNetwork.from_dict(network_dict)
+
+		# Compare.
+		self.assertTrue(network.deep_equal_to(dict_network))
+
+	def test_assembly_3_stage(self):
+		"""Test that to_dict() and from_dict() correctly convert SupplyChainNetwork object to and from dict
+		in 3-stage assembly system.
+		"""
+		print_status('TestToFromDict', 'test_assembly_3_stage()')
+
+		network = load_instance("assembly_3_stage")
+
+		# Convert network to dict.
+		network_dict = network.to_dict()
+
+		# Convert dict back to network.
+		dict_network = SupplyChainNetwork.from_dict(network_dict)
+
+		# Compare.
+		self.assertTrue(network.deep_equal_to(dict_network))
+
+	def test_example_6_1_per_22(self):
+		"""Test that to_dict() and from_dict() correctly convert SupplyChainNetwork object to and from dict
+		in Example 6.1 per 22.
+		"""
+		print_status('TestToFromDict', 'test_example_6_1_per_22()')
+
+		network = load_instance("example_6_1")
+
+		# Set initial inventory levels to local BS levels.
+		for n in network.nodes:
+			n.initial_inventory_level = n.inventory_policy.base_stock_level
+
+		# Strategy for these tests: run sim for a few periods, convert nodes
+		# to dict and back, compare to original.
+		simulation(network, 23, rand_seed=17, progress_bar=False)
+
+		# Convert network to dict.
+		network_dict = network.to_dict()
+
+		# Convert dict back to network.
+		dict_network = SupplyChainNetwork.from_dict(network_dict)
+
+		# Compare.
+		self.assertTrue(network.deep_equal_to(dict_network))
+
+	def test_assembly_3_stage_per_22(self):
+		"""Test that to_dict() and from_dict() correctly convert SupplyChainNetwork object to and from dict
+		in 3-stage assembly system.
+		"""
+		print_status('TestToFromDict', 'test_assembly_3_stage_per_22()')
+
+		network = load_instance("assembly_3_stage")
+
+		# Set initial inventory levels to local BS levels.
+		for n in network.nodes:
+			n.initial_inventory_level = n.inventory_policy.base_stock_level
+
+		# Strategy for these tests: run sim for a few periods, convert nodes
+		# to dict and back, compare to original.
+		simulation(network, 23, rand_seed=17, progress_bar=False)
+
+		# Convert network to dict.
+		network_dict = network.to_dict()
+
+		# Convert dict back to network.
+		dict_network = SupplyChainNetwork.from_dict(network_dict)
+
+		# Compare.
+		self.assertTrue(network.deep_equal_to(dict_network))
+
+