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Transport14.java
1package com.gams.examples.transport;
2
3import java.io.File;
4
5import com.gams.api.GAMSDatabase;
6import com.gams.api.GAMSException;
7import com.gams.api.GAMSJob;
8import com.gams.api.GAMSOptions;
9import com.gams.api.GAMSParameter;
10import com.gams.api.GAMSWorkspace;
11import com.gams.api.GAMSWorkspaceInfo;
12
18public class Transport14 {
19 public static void main(String[] args) {
20 initializeWorkspace(args);
21 double[] bmultlist = new double[] { 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3 };
22 Optimizer[] optim = new Optimizer[bmultlist.length];
23 for (int i=0; i<bmultlist.length; i++) {
24 optim[i] = new Optimizer(bmultlist[i]);
25 optim[i].start();
26 }
27 }
28
29 static void initializeWorkspace(String[] args) {
30 GAMSWorkspaceInfo wsInfo = new GAMSWorkspaceInfo();
31 File workingDirectory = new File(System.getProperty("user.dir"), "Transport14");
32 workingDirectory.mkdir();
33 wsInfo.setWorkingDirectory(workingDirectory.getAbsolutePath());
34 if (args.length > 0)
35 wsInfo.setSystemDirectory(args[0]);
36 Optimizer.setWorkspace( new GAMSWorkspace(wsInfo) );
37 }
38}
39
43class Optimizer extends Thread {
44 static GAMSWorkspace workspace = null;
45 double bmult = 0.0;
46
47 static void setWorkspace(GAMSWorkspace ws) {
48 workspace = ws;
49 }
50
51 public Optimizer(double mult) {
52 if (workspace == null)
53 throw new GAMSException("no workspace information, initialize workspace before creating an Optimizer");
54 bmult = mult;
55 }
56
57 public void run() {
58 GAMSDatabase gDb = workspace.addDatabase();
59
60 GAMSParameter f = gDb.addParameter("f", "freight in dollars per case per thousand miles");
61 f.addRecord().setValue( 90 * bmult );
62
63 GAMSJob gModJob = workspace.addJobFromString( model );
64
65 GAMSOptions gOption = workspace.addOptions();
66 gOption.defines("gdxincname", gDb.getName());
67 gModJob.run(gOption, gDb);
68
69 double obj = gModJob.OutDB().getVariable("z").getFirstRecord().getLevel();
70 System.out.println("Scenario bmult=" + bmult + ", Obj=" + obj);
71
72 // dispose option and databases
73 gOption.dispose();
74 gDb.dispose();
75 gModJob.OutDB().dispose();
76 }
77
78 static String model =
79 "Sets \n"+
80 " i canning plants / seattle, san-diego / \n"+
81 " j markets / new-york, chicago, topeka / ; \n"+
82 " \n"+
83 "Parameters \n"+
84 " \n"+
85 " a(i) capacity of plant i in cases \n"+
86 " / seattle 350 \n"+
87 " san-diego 600 / \n"+
88 " \n"+
89 " b(j) demand at market j in cases \n"+
90 " / new-york 325 \n"+
91 " chicago 300 \n"+
92 " topeka 275 / ; \n"+
93 " \n"+
94 "Table d(i,j) distance in thousands of miles \n"+
95 " new-york chicago topeka \n"+
96 " seattle 2.5 1.7 1.8 \n"+
97 " san-diego 2.5 1.8 1.4 ; \n"+
98 " \n"+
99 "Scalar f freight in dollars per case per thousand miles; \n"+
100 " \n"+
101 "$if not set gdxincname $abort 'no include file name for data file provided' \n"+
102 "$gdxin %gdxincname% \n"+
103 "$load f \n"+
104 "$gdxin \n"+
105 " \n"+
106 "Parameter c(i,j) transport cost in thousands of dollars per case ; \n"+
107 " \n"+
108 " c(i,j) = f * d(i,j) / 1000 ; \n"+
109 " \n"+
110 "Variables \n"+
111 " x(i,j) shipment quantities in cases \n"+
112 " z total transportation costs in thousands of dollars ; \n"+
113 " \n"+
114 "Positive Variable x ; \n"+
115 " \n"+
116 "Equations \n"+
117 " cost define objective function \n"+
118 " supply(i) observe supply limit at plant i \n"+
119 " demand(j) satisfy demand at market j ; \n"+
120 " \n"+
121 "cost .. z =e= sum((i,j), c(i,j)*x(i,j)) ; \n"+
122 " \n"+
123 "supply(i) .. sum(j, x(i,j)) =l= a(i) ; \n"+
124 " \n"+
125 "demand(j) .. sum(i, x(i,j)) =g= b(j) ; \n"+
126 " \n"+
127 "Model transport /all/ ; \n"+
128 " \n"+
129 "Solve transport using lp minimizing z ; \n"+
130 " \n"+
131 "Display x.l, x.m ; \n"+
132 " \n";
133}
com::gams::api::GAMSDatabase::addParameter
GAMSParameter addParameter(String identifier, int dimension)
com::gams::api::GAMSOptions::defines
void defines(String defStr, String asStr)
com::gams::api::GAMSSymbol::addRecord
T addRecord(Vector< String > keys)
com::gams::api::GAMSWorkspaceInfo::setSystemDirectory
void setSystemDirectory(String directory)
com::gams::api::GAMSWorkspaceInfo::setWorkingDirectory
void setWorkingDirectory(String directory)
com::gams::api::GAMSWorkspace::addJobFromString
GAMSJob addJobFromString(String source)
com::gams.examples.transport.Transport14
This example shows how to run multiple GAMSJobs in parallel each using different scenario.
Definition: Transport14.java:18
com::gams
Provides package namespace for Java interface and examples to General Algebraic Model System (GAMS).
com
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