Supply Chain With a Manufacturer
This example shows how to create a complete supply chain with a raw-material supplier, a manufacturer, a distributor and a customer demand.
Creating Nodes
In this scenario, we create a raw-material supplier with finite inventory. A raw-material supplier with finite inventory needs a raw material, which is created first. The raw material is defined by its ID, its name, how many units are mined in each round of mining (extraction_quantity), how long each round takes (extraction_time), the mining cost per unit, and the sell price per unit (cost). The raw-material supplier mines a single raw material. It mines whenever its inventory is not full, and starts again as soon as its inventory drops.
import SupplyNetPy.Components as scm
raw_mat1 = scm.RawMaterial(ID='rm1', name='raw_mat1', extraction_quantity=1000,
extraction_time=1, mining_cost=0.5, cost=0.8)
supplier1 = {'ID':'S1', 'name':'supplier1', 'node_type':'supplier', 'capacity':5000,
'initial_level':5000, 'inventory_holding_cost':0.01, 'raw_material':raw_mat1}
Creating a manufacturer requires a product. The product, the manufacturer and the distributor are created below. In the code, the manufacturer has the node type "factory", which means the same as "manufacturer".
product1 = scm.Product(ID='p1', name='product1', manufacturing_cost=20, manufacturing_time=1,
batch_size=1000, raw_materials=[(raw_mat1, 2)], sell_price=30)
factory1 = {'ID':'F1', 'name':'factory1', 'node_type':'factory',
'capacity':2500, 'initial_level':2500, 'inventory_holding_cost':0.02,
'replenishment_policy':scm.SSReplenishment, 'policy_param': {'s':1000,'S':2500},
'product':product1, 'product_sell_price':30}
distributor1 = {'ID': 'D1', 'name': 'Distributor1', 'node_type': 'distributor',
'capacity': 1000, 'initial_level': 1000, 'inventory_holding_cost': 0.2,
'replenishment_policy': scm.SSReplenishment, 'policy_param': {'s':300,'S':1000},
'product_buy_price':30,'product_sell_price': 35}
The manufacturer plans its production with a replenishment policy, here an (s, S) policy. When the inventory position of its product falls to s (1000) or below, it plans enough production to bring the inventory position back up to S (2500), and orders the raw materials needed. Each unit of the product needs 2 units of the raw material. The manufacturer makes the planned units in production batches of at most 1000 units, each taking 1 time unit. The distributor also follows an (s, S) policy, with s = 300 and S = 1000.
Defining Links
Links carry units from one site to another, each with its own transportation cost and lead time.
links1f1 = {'ID': 'L1', 'source': 'S1', 'sink': 'F1', 'cost': 100, 'lead_time': lambda: 2}
linkf1d1 = {'ID': 'L2', 'source': 'F1', 'sink': 'D1', 'cost': 120, 'lead_time': lambda: 3}
Modeling Demand
The customer demand is at the distributor, with a customer order of 30 units every 0.4 time units (fixed, with no randomness).
demand1 = {'ID': 'd1', 'name': 'Demand1', 'order_arrival_model': lambda: 0.4,
'order_quantity_model': lambda: 30, 'demand_node': 'D1'}
Running the Simulation
Create the supply chain network and simulate it.
supplychainnet = scm.create_sc_net(nodes=[supplier1, factory1, distributor1],
links=[links1f1, linkf1d1], demands=[demand1])
supplychainnet = scm.simulate_sc_net(supplychainnet, sim_time=20, logging=True)
Review Results
Here is the simulation log produced by the network.
INFO F1 - 0.0000:F1: Inventory levels:2500, on hand:2500
INFO D1 - 0.0000:D1: Inventory levels:1000, on hand:1000
INFO d1 - 0.0000:d1:Customer1:Order quantity:30, available.
INFO D1 - 0.0000:D1: Inventory levels:970, on hand:970
INFO d1 - 0.4000:d1:Customer2:Order quantity:30, available.
INFO D1 - 0.4000:D1: Inventory levels:940, on hand:940
INFO d1 - 0.8000:d1:Customer3:Order quantity:30, available.
INFO D1 - 0.8000:D1: Inventory levels:910, on hand:910
INFO S1 - 1.0000:S1: Inventory level:5000
INFO d1 - 1.2000:d1:Customer4:Order quantity:30, available.
INFO D1 - 1.2000:D1: Inventory levels:880, on hand:880
INFO d1 - 1.6000:d1:Customer5:Order quantity:30, available.
INFO D1 - 1.6000:D1: Inventory levels:850, on hand:850
INFO S1 - 2.0000:S1: Inventory level:5000
INFO d1 - 2.0000:d1:Customer6:Order quantity:30, available.
INFO D1 - 2.0000:D1: Inventory levels:820, on hand:820
INFO d1 - 2.4000:d1:Customer7:Order quantity:30, available.
INFO D1 - 2.4000:D1: Inventory levels:790, on hand:790
INFO d1 - 2.8000:d1:Customer8:Order quantity:30, available.
INFO D1 - 2.8000:D1: Inventory levels:760, on hand:760
INFO S1 - 3.0000:S1: Inventory level:5000
INFO d1 - 3.2000:d1:Customer9:Order quantity:30, available.
INFO D1 - 3.2000:D1: Inventory levels:730, on hand:730
INFO d1 - 3.6000:d1:Customer10:Order quantity:30, available.
INFO D1 - 3.6000:D1: Inventory levels:700, on hand:700
INFO d1 - 4.0000:d1:Customer11:Order quantity:30, available.
INFO D1 - 4.0000:D1: Inventory levels:670, on hand:670
INFO S1 - 4.0000:S1: Inventory level:5000
INFO d1 - 4.4000:d1:Customer12:Order quantity:30, available.
INFO D1 - 4.4000:D1: Inventory levels:640, on hand:640
INFO d1 - 4.8000:d1:Customer13:Order quantity:30, available.
INFO D1 - 4.8000:D1: Inventory levels:610, on hand:610
INFO S1 - 5.0000:S1: Inventory level:5000
INFO d1 - 5.2000:d1:Customer14:Order quantity:30, available.
INFO D1 - 5.2000:D1: Inventory levels:580, on hand:580
INFO d1 - 5.6000:d1:Customer15:Order quantity:30, available.
INFO D1 - 5.6000:D1: Inventory levels:550, on hand:550
INFO S1 - 6.0000:S1: Inventory level:5000
INFO d1 - 6.0000:d1:Customer16:Order quantity:30, available.
INFO D1 - 6.0000:D1: Inventory levels:520, on hand:520
INFO d1 - 6.4000:d1:Customer17:Order quantity:30, available.
INFO D1 - 6.4000:D1: Inventory levels:490, on hand:490
INFO d1 - 6.8000:d1:Customer18:Order quantity:30, available.
INFO D1 - 6.8000:D1: Inventory levels:460, on hand:460
INFO S1 - 7.0000:S1: Inventory level:5000
INFO d1 - 7.2000:d1:Customer19:Order quantity:30, available.
INFO D1 - 7.2000:D1: Inventory levels:430, on hand:430
INFO d1 - 7.6000:d1:Customer20:Order quantity:30, available.
INFO D1 - 7.6000:D1: Inventory levels:400, on hand:400
INFO S1 - 8.0000:S1: Inventory level:5000
INFO d1 - 8.0000:d1:Customer21:Order quantity:30, available.
INFO D1 - 8.0000:D1: Inventory levels:370, on hand:370
INFO d1 - 8.4000:d1:Customer22:Order quantity:30, available.
INFO D1 - 8.4000:D1: Inventory levels:340, on hand:340
INFO d1 - 8.8000:d1:Customer23:Order quantity:30, available.
INFO D1 - 8.8000:D1: Inventory levels:310, on hand:310
INFO S1 - 9.0000:S1: Inventory level:5000
INFO d1 - 9.2000:d1:Customer24:Order quantity:30, available.
INFO D1 - 9.2000:D1: Inventory levels:280, on hand:280
INFO D1 - 9.2000:D1:Replenishing inventory from supplier:factory1, order placed for 720 units.
INFO D1 - 9.2000:D1:shipment in transit from supplier:factory1.
INFO F1 - 9.2000:F1: Inventory levels:1780, on hand:1780
INFO d1 - 9.6000:d1:Customer25:Order quantity:30, available.
INFO D1 - 9.6000:D1: Inventory levels:250, on hand:970
INFO S1 - 10.0000:S1: Inventory level:5000
INFO d1 - 10.0000:d1:Customer26:Order quantity:30, available.
INFO D1 - 10.0000:D1: Inventory levels:220, on hand:940
INFO d1 - 10.4000:d1:Customer27:Order quantity:30, available.
INFO D1 - 10.4000:D1: Inventory levels:190, on hand:910
INFO d1 - 10.8000:d1:Customer28:Order quantity:30, available.
INFO D1 - 10.8000:D1: Inventory levels:160, on hand:880
INFO S1 - 11.0000:S1: Inventory level:5000
INFO d1 - 11.2000:d1:Customer29:Order quantity:30, available.
INFO D1 - 11.2000:D1: Inventory levels:130, on hand:850
INFO d1 - 11.6000:d1:Customer30:Order quantity:30, available.
INFO D1 - 11.6000:D1: Inventory levels:100, on hand:820
INFO S1 - 12.0000:S1: Inventory level:5000
INFO d1 - 12.0000:d1:Customer31:Order quantity:30, available.
INFO D1 - 12.0000:D1: Inventory levels:70, on hand:790
INFO D1 - 12.2000:D1:Inventory replenished. reorder_quantity=720, Inventory levels:790
INFO d1 - 12.4000:d1:Customer32:Order quantity:30, available.
INFO D1 - 12.4000:D1: Inventory levels:760, on hand:760
INFO d1 - 12.8000:d1:Customer33:Order quantity:30, available.
INFO D1 - 12.8000:D1: Inventory levels:730, on hand:730
INFO S1 - 13.0000:S1: Inventory level:5000
INFO d1 - 13.2000:d1:Customer34:Order quantity:30, available.
INFO D1 - 13.2000:D1: Inventory levels:700, on hand:700
INFO d1 - 13.6000:d1:Customer35:Order quantity:30, available.
INFO D1 - 13.6000:D1: Inventory levels:670, on hand:670
INFO S1 - 14.0000:S1: Inventory level:5000
INFO d1 - 14.0000:d1:Customer36:Order quantity:30, available.
INFO D1 - 14.0000:D1: Inventory levels:640, on hand:640
INFO d1 - 14.4000:d1:Customer37:Order quantity:30, available.
INFO D1 - 14.4000:D1: Inventory levels:610, on hand:610
INFO d1 - 14.8000:d1:Customer38:Order quantity:30, available.
INFO D1 - 14.8000:D1: Inventory levels:580, on hand:580
INFO S1 - 15.0000:S1: Inventory level:5000
INFO d1 - 15.2000:d1:Customer39:Order quantity:30, available.
INFO D1 - 15.2000:D1: Inventory levels:550, on hand:550
INFO d1 - 15.6000:d1:Customer40:Order quantity:30, available.
INFO D1 - 15.6000:D1: Inventory levels:520, on hand:520
INFO S1 - 16.0000:S1: Inventory level:5000
INFO d1 - 16.0000:d1:Customer41:Order quantity:30, available.
INFO D1 - 16.0000:D1: Inventory levels:490, on hand:490
INFO d1 - 16.4000:d1:Customer42:Order quantity:30, available.
INFO D1 - 16.4000:D1: Inventory levels:460, on hand:460
INFO d1 - 16.8000:d1:Customer43:Order quantity:30, available.
INFO D1 - 16.8000:D1: Inventory levels:430, on hand:430
INFO S1 - 17.0000:S1: Inventory level:5000
INFO d1 - 17.2000:d1:Customer44:Order quantity:30, available.
INFO D1 - 17.2000:D1: Inventory levels:400, on hand:400
INFO d1 - 17.6000:d1:Customer45:Order quantity:30, available.
INFO D1 - 17.6000:D1: Inventory levels:370, on hand:370
INFO S1 - 18.0000:S1: Inventory level:5000
INFO d1 - 18.0000:d1:Customer46:Order quantity:30, available.
INFO D1 - 18.0000:D1: Inventory levels:340, on hand:340
INFO d1 - 18.4000:d1:Customer47:Order quantity:30, available.
INFO D1 - 18.4000:D1: Inventory levels:310, on hand:310
INFO d1 - 18.8000:d1:Customer48:Order quantity:30, available.
INFO D1 - 18.8000:D1: Inventory levels:280, on hand:280
INFO D1 - 18.8000:D1:Replenishing inventory from supplier:factory1, order placed for 720 units.
INFO D1 - 18.8000:D1:shipment in transit from supplier:factory1.
INFO F1 - 18.8000:F1: Inventory levels:1060, on hand:1060
INFO S1 - 19.0000:S1: Inventory level:5000
INFO d1 - 19.2000:d1:Customer49:Order quantity:30, available.
INFO D1 - 19.2000:D1: Inventory levels:250, on hand:970
INFO d1 - 19.6000:d1:Customer50:Order quantity:30, available.
INFO D1 - 19.6000:D1: Inventory levels:220, on hand:940
INFO d1 - 20.0000:d1:Customer51:Order quantity:30, available.
INFO D1 - 20.0000:D1: Inventory levels:190, on hand:910
INFO sim_trace - Supply chain info:
INFO sim_trace - available_inv : 6250
INFO sim_trace - avg_available_inv : 7634.5
INFO sim_trace - avg_cost_per_item : 8.663434343434345
INFO sim_trace - avg_cost_per_order : 485.4792452830189
INFO sim_trace - backorders : [0, 0]
INFO sim_trace - demand_by_customers : [51, 1530]
INFO sim_trace - demand_by_site : [2, 1440]
INFO sim_trace - demands : {'d1': Demand1}
INFO sim_trace - env : <simpy.core.Environment object at 0x00000196503EB290>
INFO sim_trace - fulfillment_received_by_customers : [51, 1530]
INFO sim_trace - fulfillment_received_by_site : [1, 720]
INFO sim_trace - inventory_carry_cost : 3890.4
INFO sim_trace - inventory_spend_cost : 21600
INFO sim_trace - inventory_waste : 0
INFO sim_trace - links : {'L1': S1 to F1, 'L2': F1 to D1}
INFO sim_trace - nodes : {'S1': supplier1, 'F1': factory1, 'D1': Distributor1}
INFO sim_trace - num_distributors : 1
INFO sim_trace - num_manufacturers : 1
INFO sim_trace - num_of_links : 2
INFO sim_trace - num_of_nodes : 3
INFO sim_trace - num_retailers : 0
INFO sim_trace - num_suppliers : 1
INFO sim_trace - profit : 49419.6
INFO sim_trace - revenue : 75150.0
INFO sim_trace - shortage : [0, 0]
INFO sim_trace - total_cost : 25730.4
INFO sim_trace - total_demand : [53, 2970]
INFO sim_trace - total_fulfillment_received : [52, 2250]
INFO sim_trace - transportation_cost : 240