transport4.cpp
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26 #include "gams.h"
27 #include <iostream>
28 #include <fstream>
29 #include <vector>
30 #include <map>
31 
32 using namespace gams;
33 using namespace std;
34 
36 string getModelText()
37 {
38  return "Sets \n"
39  " i canning plants \n"
40  " j markets \n"
41  " \n"
42  "Parameters \n"
43  " a(i) capacity of plant i in cases \n"
44  " b(j) demand at market j in cases \n"
45  " d(i,j) distance in thousands of miles \n"
46  "Scalar f freight in dollars per case per thousand miles; \n"
47  " \n"
48  "$if not set gdxincname $abort 'no include file name for data file provided'\n"
49  "$gdxin %gdxincname% \n"
50  "$load i j a b d f \n"
51  "$gdxin \n"
52  " \n"
53  " Parameter c(i,j) transport cost in thousands of dollars per case ; \n"
54  " \n"
55  " c(i,j) = f * d(i,j) / 1000 ; \n"
56  " \n"
57  " Variables \n"
58  " x(i,j) shipment quantities in cases \n"
59  " z total transportation costs in thousands of dollars ; \n"
60  " \n"
61  " Positive Variable x ; \n"
62  " \n"
63  " Equations \n"
64  " \n"
65  " cost define objective function \n"
66  " supply(i) observe supply limit at plant i \n"
67  " demand(j) satisfy demand at market j ; \n"
68  " \n"
69  " cost .. z =e= sum((i,j), c(i,j)*x(i,j)) ; \n"
70  " \n"
71  " supply(i) .. sum(j, x(i,j)) =l= a(i) ; \n"
72  " \n"
73  " demand(j) .. sum(i, x(i,j)) =g= b(j) ; \n"
74  " \n"
75  " Model transport /all/ ; \n"
76  " \n"
77  " Solve transport using lp minimizing z ; \n"
78  " \n"
79  "Display x.l, x.m ; \n";
80 }
81 
88 int main(int argc, char* argv[])
89 {
90  cout << "---------- Transport 4 --------------" << endl;
91 
92  try {
93  GAMSWorkspaceInfo wsInfo;
94  if (argc > 1)
95  wsInfo.setSystemDirectory(argv[1]);
96  GAMSWorkspace ws(wsInfo);
97 
98  // define some data by using C++ data structures
99  vector<string> plants = {
100  "Seattle", "San-Diego"
101  };
102  vector<string> markets = {
103  "New-York", "Chicago", "Topeka"
104  };
105  map<string, double> capacity = {
106  { "Seattle", 350.0 }, { "San-Diego", 600.0 }
107  };
108  map<string, double> demand = {
109  { "New-York", 325.0 }, { "Chicago", 300.0 }, { "Topeka", 275.0 }
110  };
111  map<tuple<string, string>, double> distance = {
112  { make_tuple("Seattle", "New-York"), 2.5 },
113  { make_tuple("Seattle", "Chicago"), 1.7 },
114  { make_tuple("Seattle", "Topeka"), 1.8 },
115  { make_tuple("San-Diego", "New-York"), 2.5 },
116  { make_tuple("San-Diego", "Chicago"), 1.8 },
117  { make_tuple("San-Diego", "Topeka"), 1.4 }
118  };
119 
120  // prepare a GAMSDatabase with data from the C++ data structures
121  GAMSDatabase db = ws.addDatabase();
122 
123  GAMSSet i = db.addSet("i", 1, "canning plants");
124  for (string p: plants)
125  i.addRecord(p);
126 
127  GAMSSet j = db.addSet("j", 1, "markets");
128  for (string m: markets)
129  j.addRecord(m);
130 
131  GAMSParameter a = db.addParameter("a", "capacity of plant i in cases", i);
132  for (string p: plants)
133  a.addRecord(p).setValue(capacity[p]);
134 
135  GAMSParameter b = db.addParameter("b", "demand at market j in cases", j);
136  for (string m: markets)
137  b.addRecord(m).setValue(demand[m]);
138 
139  GAMSParameter d = db.addParameter("d", "distance in thousands of miles", i, j);
140  for (auto t : distance)
141  d.addRecord(get<0>(t.first), get<1>(t.first)).setValue(t.second);
142 
143  GAMSParameter f = db.addParameter("f", "freight in dollars per case per thousand miles");
144  f.addRecord().setValue(90);
145 
146  // run a job using data from the created GAMSDatabase
147  GAMSJob t4 = ws.addJobFromString(getModelText());
148  GAMSOptions opt = ws.addOptions();
149  opt.setDefine("gdxincname", db.name());
150  opt.setAllModelTypes("xpress");
151  t4.run(opt, db);
152 
153  for (GAMSVariableRecord rec : t4.outDB().getVariable("x"))
154  cout << "x(" << rec.key(0) << "," << rec.key(1) << "):" << " level=" << rec.level() << " marginal="
155  << rec.marginal() << endl;
156 
157  } catch (GAMSException &ex) {
158  cout << "GAMSException occured: " << ex.what() << endl;
159  } catch (exception &ex) {
160  cout << ex.what() << endl;
161  }
162 
163  return 0;
164 }
void setSystemDirectory(std::string systemDir)
GAMSVariable getVariable(const std::string &name)
void setAllModelTypes(const std::string &solver)
GAMSSet addSet(const std::string &name, const int dimension, const std::string &explanatoryText="", GAMSEnum::SetType setType=GAMSEnum::SetType::Multi)
GAMSParameterRecord addRecord(const std::vector< std::string > &keys)
GAMSDatabase outDB()
GAMSSetRecord addRecord(const std::vector< std::string > &keys)
GAMSParameter addParameter(const std::string &name, const int dimension, const std::string &explanatoryText="")
void setValue(const double val)
void setDefine(const std::string &key, const std::string &value)
string getModelText()
Get model as string.
Definition: transport4.cpp:36
std::string name()