lemon-project-template-glpk

comparison deps/glpk/examples/transp.mod @ 10:5545663ca997

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Configure GLPK build
author Alpar Juttner <alpar@cs.elte.hu>
date Sun, 06 Nov 2011 21:42:23 +0100 (2011-11-06)
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1 # A TRANSPORTATION PROBLEM
2 #
3 # This problem finds a least cost shipping schedule that meets
4 # requirements at markets and supplies at factories.
5 #
6 # References:
7 # Dantzig G B, "Linear Programming and Extensions."
8 # Princeton University Press, Princeton, New Jersey, 1963,
9 # Chapter 3-3.
10
11 set I;
12 /* canning plants */
13
14 set J;
15 /* markets */
16
17 param a{i in I};
18 /* capacity of plant i in cases */
19
20 param b{j in J};
21 /* demand at market j in cases */
22
23 param d{i in I, j in J};
24 /* distance in thousands of miles */
25
26 param f;
27 /* freight in dollars per case per thousand miles */
28
29 param c{i in I, j in J} := f * d[i,j] / 1000;
30 /* transport cost in thousands of dollars per case */
31
32 var x{i in I, j in J} >= 0;
33 /* shipment quantities in cases */
34
35 minimize cost: sum{i in I, j in J} c[i,j] * x[i,j];
36 /* total transportation costs in thousands of dollars */
37
38 s.t. supply{i in I}: sum{j in J} x[i,j] <= a[i];
39 /* observe supply limit at plant i */
40
41 s.t. demand{j in J}: sum{i in I} x[i,j] >= b[j];
42 /* satisfy demand at market j */
43
44 data;
45
46 set I := Seattle San-Diego;
47
48 set J := New-York Chicago Topeka;
49
50 param a := Seattle 350
51 San-Diego 600;
52
53 param b := New-York 325
54 Chicago 300
55 Topeka 275;
56
57 param d : New-York Chicago Topeka :=
58 Seattle 2.5 1.7 1.8
59 San-Diego 2.5 1.8 1.4 ;
60
61 param f := 90;
62
63 end;