1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
/********************* */
/*! \file tableau.h
** \verbatim
** Original author: taking
** Major contributors: mdeters
** Minor contributors (to current version): dejan
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010 The Analysis of Computer Systems Group (ACSys)
** Courant Institute of Mathematical Sciences
** New York University
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief [[ Add one-line brief description here ]]
**
** [[ Add lengthier description here ]]
** \todo document this file
**/
#include "expr/node.h"
#include "expr/attribute.h"
#include "theory/arith/arith_utilities.h"
#include "theory/arith/arith_activity.h"
#include "theory/arith/basic.h"
#include "theory/arith/normal_form.h"
#include <ext/hash_map>
#include <map>
#include <set>
#ifndef __CVC4__THEORY__ARITH__TABLEAU_H
#define __CVC4__THEORY__ARITH__TABLEAU_H
namespace CVC4 {
namespace theory {
namespace arith {
class Row {
ArithVar d_x_i;
typedef std::map<ArithVar, Rational, std::greater<ArithVar> > CoefficientTable;
CoefficientTable d_coeffs;
public:
typedef CoefficientTable::iterator iterator;
/**
* Construct a row equal to:
* basic = \sum_{x_i} c_i * x_i
*/
Row(ArithVar basic,
const std::vector< Rational >& coefficients,
const std::vector< ArithVar >& variables);
iterator begin(){
return d_coeffs.begin();
}
iterator end(){
return d_coeffs.end();
}
ArithVar basicVar(){
return d_x_i;
}
bool has(ArithVar x_j){
CoefficientTable::iterator x_jPos = d_coeffs.find(x_j);
return x_jPos != d_coeffs.end();
}
const Rational& lookup(ArithVar x_j){
CoefficientTable::iterator x_jPos = d_coeffs.find(x_j);
Assert(x_jPos != d_coeffs.end());
return (*x_jPos).second;
}
void pivot(ArithVar x_j);
void subsitute(Row& row_s);
void printRow();
};
class Tableau {
public:
typedef std::set<ArithVar> VarSet;
private:
typedef __gnu_cxx::hash_map<ArithVar, Row*> RowsTable;
VarSet d_activeBasicVars;
RowsTable d_activeRows, d_inactiveRows;
ActivityMonitor& d_activityMonitor;
IsBasicManager& d_basicManager;
public:
/**
* Constructs an empty tableau.
*/
Tableau(ActivityMonitor &am, IsBasicManager& bm) :
d_activeBasicVars(),
d_activeRows(),
d_inactiveRows(),
d_activityMonitor(am),
d_basicManager(bm)
{}
VarSet::iterator begin(){
return d_activeBasicVars.begin();
}
VarSet::iterator end(){
return d_activeBasicVars.end();
}
Row* lookup(ArithVar var){
Assert(isActiveBasicVariable(var));
return d_activeRows[var];
}
private:
Row* lookupEjected(ArithVar var){
Assert(isEjected(var));
return d_inactiveRows[var];
}
public:
void addRow(ArithVar basicVar, const std::vector<Rational>& coeffs, const std::vector<ArithVar>& variables);
/**
* preconditions:
* x_r is basic,
* x_s is non-basic, and
* a_rs != 0.
*/
void pivot(ArithVar x_r, ArithVar x_s);
void printTableau();
bool isEjected(ArithVar var){
return d_inactiveRows.find(var) != d_inactiveRows.end();
}
void ejectBasic(ArithVar basic){
Assert(d_basicManager.isBasic(basic));
Assert(isActiveBasicVariable(basic));
Row* row = lookup(basic);
d_activeRows.erase(basic);
d_activeBasicVars.erase(basic);
d_inactiveRows.insert(std::make_pair(basic, row));
}
void reinjectBasic(ArithVar basic){
Assert(d_basicManager.isBasic(basic));
Assert(isEjected(basic));
Row* row = lookupEjected(basic);
d_inactiveRows.erase(basic);
d_activeBasicVars.insert(basic);
d_activeRows.insert(std::make_pair(basic, row));
updateRow(row);
}
private:
inline bool isActiveBasicVariable(ArithVar var){
return d_activeBasicVars.find(var) != d_activeBasicVars.end();
}
void updateRow(Row* row);
};
}; /* namespace arith */
}; /* namespace theory */
}; /* namespace CVC4 */
#endif /* __CVC4__THEORY__ARITH__TABLEAU_H */
|
