Skip to content

Logistics

2 of the bundled models. The numbers are from a run made when this page was generated: see how.

Warehouse with forklifts (floor plan)

A small warehouse on a real-metre floor plan: pallets are unloaded at the dock, driven by forklift to one of two storage zones, driven again to picking, and leave on a take-away conveyor to shipping. Travel time is geometry -- distance along the aisle network divided by the forklift speed -- so moving the dock or adding a truck changes the KPIs the way hand reasoning says it should.

naga run warehouse_forklifts --replications 3

flowchart LR
    b0["pallets_fast (CREATE)"]
    b1["pallets_bulk (CREATE)"]
    b2["to_first_stop (ROUTE)"]
    b3["Dock (STATION)"]
    b4["unload (PROCESS)"]
    b5["Storage A (STATION)"]
    b6["putaway_a (DELAY)"]
    b7["Storage B (STATION)"]
    b8["putaway_b (DELAY)"]
    b9["Picking (STATION)"]
    b10["pick_order (PROCESS)"]
    b11["forklift_move (TRANSPORT)"]
    b12["takeaway_belt (CONVEYOR)"]
    b13["Shipping (STATION)"]
    b14["load_truck (PROCESS)"]
    b15["shipped (DISPOSE)"]
    b0 --> b2
    b1 --> b2
    b2 --> b15
    b3 --> b4
    b4 --> b11
    b5 --> b6
    b6 --> b11
    b7 --> b8
    b8 --> b11
    b9 --> b10
    b10 --> b11
    b11 --> b12
    b12 --> b13
    b13 --> b14
    b14 --> b15

3 replications, seed 0:

KPI Mean 95% half-width
system/Total Entities Completed 306 19
system/Avg Throughput Time 23.8 1.9
system/Avg Queue Length 1.17 0.75
system/Avg Resource Usage % 63.4 4.1
system/Total Cost 3,700 73

Order-driven warehouse (library assets)

An order-driven warehouse built from the Logistics library alone: inbound trucks, a receiving dock, forklifts putting pallets away into two rack zones that HOLD them as stock, customer orders drawing that stock with backorders when it is short, order picking, a take-away belt and an outbound dock that consolidates truck loads. Inbound and outbound are two entity streams that meet at each zone's level; each asset brought its own network node when it was placed, and the aisles joining them are the only geometry drawn by hand.

naga run warehouse_library --replications 3

flowchart LR
    b0["trucks_fast (SUBMODEL)"]
    b1["trucks_bulk (SUBMODEL)"]
    b2["dock (SUBMODEL)"]
    b3["zone_a (SUBMODEL)"]
    b4["zone_b (SUBMODEL)"]
    b5["orders_fast (SUBMODEL)"]
    b6["orders_bulk (SUBMODEL)"]
    b7["pick_a (SUBMODEL)"]
    b8["pick_b (SUBMODEL)"]
    b9["belt (SUBMODEL)"]
    b10["shipping (SUBMODEL)"]
    b11["forklifts (SUBMODEL)"]
    b12["left_site (DISPOSE)"]
    b0 --> b2
    b1 --> b2
    b2 --> b11
    b3 --> b12
    b4 --> b12
    b11 --> b12
    b5 --> b7
    b6 --> b8
    b7 --> b9
    b8 --> b9
    b9 --> b10
    b10 --> b12

3 replications, seed 0:

KPI Mean 95% half-width
system/Total Entities Completed 435 35
system/Avg Throughput Time 44.7 25
system/Avg Queue Length 6.15 1.3
system/Avg Resource Usage % 46.4 2.2
user/pick_a/Log fill rate 0.98 0.045
user/pick_a/Log backorder time 0.117 0.36
user/pick_b/Log fill rate 0.8 0.86
level/zone_a/Log Zone stock/Average 12.5 11
level/zone_b/Log Zone stock/Average 29.6 54
system/Total Cost 1,070 13