Download here in PDF

Transcript
520 CHAPTER 12
Logistics Models
Capacitated Plant Location
Model: CAPLOC
Background
The capacitated plant location model is a generalization of the transportation model we introduced in
Chapter 1, Getting Started with LINGO. The capacitated plant location problem allows greater latitude
of decision making in that the points of origin (plant locations) are variable. Manufacturers and
wholesale businesses are likely to encounter problems of this sort in matching existing customer
demand to product availability and minimizing transportation costs.
The Problem in Words
Your firm has a choice of three locations to operate a manufacturing facility in. Four customers exist
with a known demand for your product. Each potential plant location has an associated monthly
operating cost, and shipping routes to the demand cities have varying costs. In addition, each potential
plant will have a shipping capacity that must not be exceeded. You need to determine what plant(s) to
open and how much of a product to send from each open plant to each customer to minimize total
shipping costs and fixed plant operating costs.
The Model
MODEL:
! Capacitated Plant Location Problem;
SETS:
PLANTS: FCOST, CAP, OPEN;
CUSTOMERS: DEM;
ARCS( PLANTS, CUSTOMERS) : COST, VOL;
ENDSETS
DATA:
! The plant, their fixed costs
and capacity;
PLANTS, FCOST, CAP =
P1
91
39
P2
70
35
P3
24
31;
! Customers and their demands;
CUSTOMERS, DEM =
C1
15
C2
17
C3
22
C4
12;
! The plant to cust cost/unit
shipment matrix;
COST =
6 2 6 7
4 9 5 3
8 8 1 5;
ENDDATA
! The objective;
[TTL_COST] MIN = @SUM( ARCS: COST * VOL) +
@SUM( PLANTS: FCOST * OPEN);