optimizer.cpp
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1/*
2 * GAMS - General Algebraic Modeling System C++ API
3 *
4 * Copyright (c) 2017 GAMS Software GmbH <support@gams.com>
5 * Copyright (c) 2017 GAMS Development Corp. <support@gams.com>s
6 *
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8 * of this software and associated documentation files (the "Software"), to deal
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15 * copies or substantial portions of the Software.
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24 */
25#include "optimizer.h"
26
27#include <iostream>
28#include <thread>
29
30using namespace gams;
31using namespace std;
32
35Optimizer::Optimizer(int argc, char *argv[])
36{
37 GAMSWorkspaceInfo wsInfo;
38 if (argc > 1)
39 wsInfo.setSystemDirectory(argv[1]);
40 ws = GAMSWorkspace(wsInfo);
41}
42
43double Optimizer::solve(double mult)
44{
45 GAMSDatabase gDb = ws.addDatabase();
46
47 GAMSParameter f = gDb.addParameter("f", "freight in dollars per case per thousand miles");
48 f.addRecord().setValue(90 * mult);
49
50 GAMSJob gModJob = ws.addJobFromString(getModelText());
51
52 GAMSOptions gOption = ws.addOptions();
53 gOption.setDefine("gdxincname", gDb.name());
54 gModJob.run(gOption, gDb);
55
56 return gModJob.outDB().getVariable("z").firstRecord().level();
57}
58
59string Optimizer::getModelText()
60{
61 return " Sets \n"
62 " i canning plants / seattle, san-diego / \n"
63 " j markets / new-york, chicago, topeka / ; \n"
64 " \n"
65 " Parameters \n"
66 " \n"
67 " a(i) capacity of plant i in cases \n"
68 " / seattle 350 \n"
69 " san-diego 600 / \n"
70 " \n"
71 " b(j) demand at market j in cases \n"
72 " / new-york 325 \n"
73 " chicago 300 \n"
74 " topeka 275 / ; \n"
75 " \n"
76 " Table d(i,j) distance in thousands of miles \n"
77 " new-york chicago topeka \n"
78 " seattle 2.5 1.7 1.8 \n"
79 " san-diego 2.5 1.8 1.4 ; \n"
80 " \n"
81 " Scalar f freight in dollars per case per thousand miles; \n"
82 " \n"
83 "$if not set gdxincname $abort 'no include file name for data file provided'\n"
84 "$gdxin %gdxincname% \n"
85 "$load f \n"
86 "$gdxin \n"
87 " \n"
88 " Parameter c(i,j) transport cost in thousands of dollars per case ; \n"
89 " \n"
90 " c(i,j) = f * d(i,j) / 1000 ; \n"
91 " \n"
92 " Variables \n"
93 " x(i,j) shipment quantities in cases \n"
94 " z total transportation costs in thousands of dollars ; \n"
95 " \n"
96 " Positive Variable x ; \n"
97 " \n"
98 " Equations \n"
99 " cost define objective function \n"
100 " supply(i) observe supply limit at plant i \n"
101 " demand(j) satisfy demand at market j ; \n"
102 " \n"
103 " cost .. z =e= sum((i,j), c(i,j)*x(i,j)) ; \n"
104 " \n"
105 " supply(i) .. sum(j, x(i,j)) =l= a(i) ; \n"
106 " \n"
107 " demand(j) .. sum(i, x(i,j)) =g= b(j) ; \n"
108 " \n"
109 " Model transport /all/ ; \n"
110 " \n"
111 " Solve transport using lp minimizing z ; \n"
112 " \n"
113 "Display x.l, x.m ; \n";
114}
void setValue(const double val)
GAMSParameter addParameter(const std::string &name, const int dimension, const std::string &explanatoryText="")
void setSystemDirectory(std::string systemDir)
std::string name()
GAMSDatabase outDB()
void setDefine(const std::string &key, const std::string &value)
GAMSVariableRecord firstRecord(const std::vector< std::string > &slice)
Wrapper class definition for executing transport14.
GAMSVariable getVariable(const std::string &name)
GAMSParameterRecord addRecord(const std::vector< std::string > &keys)