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transport5.cpp
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1
25#include "gams.h"
26#include <vector>
27#include <iostream>
28
29using namespace gams;
30using namespace std;
31
33string getModelText()
34{
35 return " Sets \n"
36 " i canning plants / seattle, san-diego / \n"
37 " j markets / new-york, chicago, topeka / ; \n"
38 " \n"
39 "Parameters \n"
40 " a(i) capacity of plant i in cases \n"
41 " / seattle 350 \n"
42 " san-diego 600 / \n"
43 " \n"
44 " b(j) demand at market j in cases \n"
45 " / new-york 325 \n"
46 " chicago 300 \n"
47 " topeka 275 / ; \n"
48 " \n"
49 "Table d(i,j) distance in thousands of miles \n"
50 " new-york chicago topeka \n"
51 " seattle 2.5 1.7 1.8 \n"
52 " san-diego 2.5 1.8 1.4 ; \n"
53 " \n"
54 "Scalar f freight in dollars per case per thousand miles /90/ ;\n"
55 "Scalar bmult demand multiplier /1/; \n"
56 " \n"
57 "Parameter c(i,j) transport cost in thousands of dollars per case ; \n"
58 " \n"
59 " c(i,j) = f * d(i,j) / 1000 ; \n"
60 " \n"
61 "Variables \n"
62 " x(i,j) shipment quantities in cases \n"
63 " z total transportation costs in thousands of dollars ; \n"
64 " \n"
65 "Positive Variable x ; \n"
66 " \n"
67 "Equations \n"
68 " cost define objective function \n"
69 " supply(i) observe supply limit at plant i \n"
70 " demand(j) satisfy demand at market j ; \n"
71 " \n"
72 "cost .. z =e= sum((i,j), c(i,j)*x(i,j)) ; \n"
73 " \n"
74 "supply(i) .. sum(j, x(i,j)) =l= a(i) ; \n"
75 " \n"
76 "demand(j) .. sum(i, x(i,j)) =g= bmult*b(j) ; \n"
77 " \n"
78 "Model transport /all/ ; \n"
79 "Scalar ms 'model status', ss 'solve status'; \n";
80}
81
88int main(int argc, char* argv[])
89{
90 cout << "---------- Transport 5 --------------" << endl;
91
92 try {
93 GAMSWorkspaceInfo wsInfo;
94 if (argc > 1)
95 wsInfo.setSystemDirectory(argv[1]);
96 GAMSWorkspace ws(wsInfo);
97 GAMSCheckpoint cp = ws.addCheckpoint();
98
99 // initialize a GAMSCheckpoint by running a GAMSJob
100 ws.addJobFromString(getModelText()).run(cp);
101
102 vector<double> bmultlist = { 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3 };
103
104 // create a new GAMSJob that is initialized from the GAMSCheckpoint
105 for (double b : bmultlist)
106 {
107 GAMSJob t5 = ws.addJobFromString("bmult=" + to_string(b) + "; solve transport min z use lp; ms=transport.modelstat; ss=transport.solvestat;", cp);
108 t5.run();
109 cout << "Scenario bmult=" << b << ":" << endl;
110 cout << " Modelstatus: " << t5.outDB().getParameter("ms").findRecord().value() << endl;
111 cout << " Solvestatus: " << t5.outDB().getParameter("ss").findRecord().value() << endl;
112 cout << " Obj: " << t5.outDB().getVariable("z").findRecord().level() << endl;
113 }
114
115 } catch (GAMSException &ex) {
116 cout << "GAMSException occured: " << ex.what() << endl;
117 } catch (exception &ex) {
118 cout << ex.what() << endl;
119 }
120
121 return 0;
122}
gams::GAMSDatabase::getParameter
GAMSParameter getParameter(const std::string &name)
gams::GAMSDatabase::getVariable
GAMSVariable getVariable(const std::string &name)
gams::GAMSJob::outDB
GAMSDatabase outDB()
gams::GAMSParameter::findRecord
GAMSParameterRecord findRecord(const std::vector< std::string > &keys)
gams::GAMSVariable::findRecord
GAMSVariableRecord findRecord(const std::vector< std::string > &keys)
gams::GAMSWorkspaceInfo::setSystemDirectory
void setSystemDirectory(std::string systemDir)
getModelText
string getModelText()
Get model as string.
Definition: transport5.cpp:33