Transportation Problem Solver

This web app - also executable via Excel interface - solves a transportation problem with Vogel's or Stelling's approximation + MODI + Stepping Stone. Those specialized methods solve a transportation problem much faster than the generic Simplex method used for solving linear programming problems. This transportation problem solver is also embedded within Centers of Gravity Calculator, a web app for running a Center of Gravity analysis in supply chain network design. At the end of this page you will find a supply chain network design case.
Download Excel interface   (70kB - downloaded 1607 times. File solves via this page, and can also create a random example.)


1
Transportation problem description and example
In a transportation problem, demand should be met by supply against minimal transportation costs. The table below shows demand, supply and the transportation cost per quantity for each supply-demand connection. In this example, total demand (350) equals total supply (350). Total supply may exceed total demand, but can never be less, otherwise the problem can not be solved! The application will warn you if in your input the total supply is less than total demand.

Demo data

COST PER
QUANTITY
 SUPPLY
141516189471520232
DEMAND4033435633618457955929189585
14285234805283440325957330796600
26431965600241190417117916631436
18763719550396200619689514108874
10484933792607322548851715802272
3081661122579851425841481500903
1889939116515565723175773048282
892232066138726760150891483407
4316504123587938706382729547310
675137825754140323229592571914
6117706414674275703395315115891
12498898858498187411717353560368
18169470643433132652898719555444
2840336860577112292422294411474
2093556944363952354960415409791
32753614610426136578118335751494
208357210857024194665176279040
3616783896329936290843395045
2851765791479678811173364930593
2746440747392946456560462798462

Optimal quantities: total costs are 102587

OPTIMAL
QUANTITIES
 SUPPLY
141516189471520232
DEMAND40492223
14194
2626
1818
1010
301614
1818
88
44
66
66
1212
18711
22
20713
3232
2020
3636
2828
22

With r referring to row, and c to column, and Xrc to the transport quantity from Supplyr  to Demandc, and Crc to the transport cost per quantity from Supplyr  to Demandc the LP problem can be formulated as:

Minimize Σ Crc × Xrc   , subject to
Σ Xrc ≥ Demandc ∀ c
c

Σ Xrc ≤ Supplyr ∀ r
r

Xrc ≥ 0 ∀ r,c
2
Input


Top-left cell = MIN (minimize costs)       1st row = supply quantities       1st column = demand quantities       All other cells = transport cost per quantity
3
Solution
Initialisation method
 

The solution will appear here, once run.
4
Visual supply chain network design case (random)
The random case will contain 10 warehouses and 1000 customers, with transportation costs per quantity = distance between warehouse and customer (instead of random costs). Generated input will appear under section 2. Hidden logic within that input enables below visualizations.
Oversupply

Final solution

  Costs:   Index:

Initial solution VOGEL

  Costs:   Index:

Initial solution STELLING

  Costs:   Index: