Transport14.java
1package com.gams.examples.transport;
2 
3 import java.io.File;
4 
5 import com.gams.api.GAMSDatabase;
6 import com.gams.api.GAMSException;
7 import com.gams.api.GAMSJob;
8 import com.gams.api.GAMSOptions;
9 import com.gams.api.GAMSParameter;
10 import com.gams.api.GAMSWorkspace;
11 import com.gams.api.GAMSWorkspaceInfo;
12 
18 public 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 
43 class 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::GAMSOptions::defines
void defines(String defStr, String asStr)
com::gams::api::GAMSWorkspaceInfo::setSystemDirectory
void setSystemDirectory(String directory)
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::api::GAMSDatabase::addParameter
GAMSParameter addParameter(String identifier, int dimension)
com::gams::api::GAMSWorkspace::addJobFromString
GAMSJob addJobFromString(String source)
com::gams::api::GAMSWorkspaceInfo::setWorkingDirectory
void setWorkingDirectory(String directory)
GAMSSymbol< GAMSParameterRecord >::addRecord
T addRecord(Vector< String > keys)