Transport5.java
1package com.gams.examples.transport;
2 
3 import java.io.File;
4 
5 import com.gams.api.GAMSCheckpoint;
6 import com.gams.api.GAMSGlobals;
7 import com.gams.api.GAMSJob;
8 import com.gams.api.GAMSWorkspace;
9 import com.gams.api.GAMSWorkspaceInfo;
10 
16 public class Transport5 {
17 
18  public static void main(String[] args) {
19  // check workspace info from command line arguments
20  GAMSWorkspaceInfo wsInfo = new GAMSWorkspaceInfo();
21  if (args.length > 0)
22  wsInfo.setSystemDirectory( args[0] );
23  // create a directory
24  File workingDirectory = new File(System.getProperty("user.dir"), "Transport5");
25  workingDirectory.mkdir();
26  wsInfo.setWorkingDirectory(workingDirectory.getAbsolutePath());
27  // create a workspace
28  GAMSWorkspace ws = new GAMSWorkspace(wsInfo);
29  // create a checkpoint
30  GAMSCheckpoint cp = ws.addCheckpoint();
31 
32  // initialize a checkpoint by running a job
33  GAMSJob t5 = ws.addJobFromString(model);
34  t5.run(cp);
35 
36  double[] bmultlist = new double[] { 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3 };
37 
38  // create a new GAMSJob that is initialized from the GAMSCheckpoint
39  for(double b : bmultlist)
40  {
41  t5 = ws.addJobFromString("bmult=" + b + "; solve transport min z use lp; ms=transport.modelstat; ss=transport.solvestat;", cp);
42  t5.run();
43 
44  System.out.println("Scenario bmult=" + b + ":");
45  System.out.println(" Modelstatus: " + GAMSGlobals.ModelStat.lookup( (int) t5.OutDB().getParameter("ms").findRecord().getValue() ));
46  System.out.println(" Solvestatus: " + GAMSGlobals.SolveStat.lookup( (int)t5.OutDB().getParameter("ss").findRecord().getValue() ));
47  System.out.println(" Obj: " + t5.OutDB().getVariable("z").findRecord().getLevel());
48  }
49 
50  }
51 
52  static String model =
53  " Sets \n"+
54  " i canning plants / seattle, san-diego / \n"+
55  " j markets / new-york, chicago, topeka / ; \n"+
56  " \n"+
57  "Parameters \n"+
58  "\n"+
59  " a(i) capacity of plant i in cases \n"+
60  " / seattle 350 \n"+
61  " san-diego 600 / \n"+
62  " \n"+
63  " b(j) demand at market j in cases \n"+
64  " / new-york 325 \n"+
65  " chicago 300 \n"+
66  " topeka 275 / ; \n"+
67  " \n"+
68  "Table d(i,j) distance in thousands of miles \n"+
69  " new-york chicago topeka \n"+
70  " seattle 2.5 1.7 1.8 \n"+
71  " san-diego 2.5 1.8 1.4 ; \n"+
72  " \n"+
73  "Scalar f freight in dollars per case per thousand miles /90/ ;\n"+
74  "Scalar bmult demand multiplier /1/; \n"+
75  " \n"+
76  "Parameter c(i,j) transport cost in thousands of dollars per case ; \n"+
77  " \n"+
78  " c(i,j) = f * d(i,j) / 1000 ; \n"+
79  " \n"+
80  "Variables \n"+
81  " x(i,j) shipment quantities in cases \n"+
82  " z total transportation costs in thousands of dollars ; \n"+
83  " \n"+
84  "Positive Variable x ; \n"+
85  " \n"+
86  "Equations \n"+
87  " cost define objective function \n"+
88  " supply(i) observe supply limit at plant i \n"+
89  " demand(j) satisfy demand at market j ; \n"+
90  " \n"+
91  "cost .. z =e= sum((i,j), c(i,j)*x(i,j)) ; \n"+
92  " \n"+
93  "supply(i) .. sum(j, x(i,j)) =l= a(i) ; \n"+
94  " \n"+
95  "demand(j) .. sum(i, x(i,j)) =g= bmult*b(j) ; \n"+
96  " \n"+
97  "Model transport /all/ ; \n"+
98  "Scalar ms 'model status', ss 'solve status'; \n";
99 
100 }
com::gams.examples.transport.Transport5
This example shows how to initialize a GAMSJob from a GAMSCheckpoint.
Definition: Transport5.java:16
com::gams::api::GAMSGlobals::ModelStat::lookup
static ModelStat lookup(int val)
com::gams::api::GAMSDatabase::getParameter
GAMSParameter getParameter(String identifier)
com::gams::api::GAMSGlobals::SolveStat::lookup
static SolveStat lookup(int val)
com::gams::api::GAMSWorkspaceInfo::setSystemDirectory
void setSystemDirectory(String directory)
com::gams::api::GAMSWorkspace::addJobFromString
GAMSJob addJobFromString(String source)
com::gams::api::GAMSWorkspace::addCheckpoint
GAMSCheckpoint addCheckpoint()
com::gams::api::GAMSWorkspaceInfo::setWorkingDirectory
void setWorkingDirectory(String directory)
com::gams::api::GAMSJob::OutDB
GAMSDatabase OutDB()
com::gams::api::GAMSDatabase::getVariable
GAMSVariable getVariable(String identifier)