gem5  v21.1.0.2
linear_solver.hh
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37 
38 #ifndef __SIM_LINEAR_SOLVER_HH__
39 #define __SIM_LINEAR_SOLVER_HH__
40 
41 #include <cassert>
42 #include <sstream>
43 #include <string>
44 #include <vector>
45 
46 namespace gem5
47 {
48 
56 {
57  public:
58  LinearEquation(unsigned unknowns) {
59  eq = std::vector <double> (unknowns + 1, 0);
60  }
61 
62  // Add two equations
64  assert(this->eq.size() == rhs.eq.size());
65 
66  LinearEquation res(this->eq.size() - 1);
67 
68  for (unsigned i = 0; i < res.eq.size(); i++)
69  res.eq[i] = this->eq[i] + rhs.eq[i];
70 
71  return res;
72  }
73 
74  // Multiply the equation by a constant
75  LinearEquation & operator*= (const double cnt) {
76  for (auto & c: eq)
77  c *= cnt;
78 
79  return *this;
80  }
81 
82  // Access a certain equation coefficient
83  double & operator[] (unsigned unkw) {
84  assert(unkw < eq.size());
85  return eq[unkw];
86  }
87 
88  // Get a string representation
89  std::string toStr() const {
90  std::ostringstream oss;
91  for (unsigned i = 0; i < eq.size(); i++) {
92  if (i)
93  oss << " + ";
94  oss << eq[i];
95  if (i != eq.size() - 1)
96  oss << "*x" << i;
97  }
98  oss << " = 0";
99  return oss.str();
100  }
101 
102  // Index for the constant term
103  unsigned cnt() const { return eq.size() - 1; }
104 
105  private:
106 
109 };
110 
112 {
113  public:
114  LinearSystem(unsigned unknowns) {
115  for (unsigned i = 0; i < unknowns; i++)
116  matrix.push_back(LinearEquation(unknowns));
117  }
118 
120  assert(eq < matrix.size());
121  return matrix[eq];
122  }
123 
124  std::string toStr() const {
125  std::string r;
126  for (auto & eq: matrix)
127  r += eq.toStr() + "\n";
128  return r;
129  }
130 
131  std::vector <double> solve() const;
132 
133  private:
135 };
136 
137 } // namespace gem5
138 
139 #endif
gem5::LinearSystem::solve
std::vector< double > solve() const
Definition: linear_solver.cc:44
gem5::LinearEquation::operator+
LinearEquation operator+(const LinearEquation &rhs)
Definition: linear_solver.hh:63
std::vector< double >
gem5::LinearSystem::LinearSystem
LinearSystem(unsigned unknowns)
Definition: linear_solver.hh:114
gem5::ArmISA::i
Bitfield< 7 > i
Definition: misc_types.hh:66
gem5::LinearEquation::eq
std::vector< double > eq
Coefficients.
Definition: linear_solver.hh:108
gem5::LinearSystem::operator[]
LinearEquation & operator[](unsigned eq)
Definition: linear_solver.hh:119
gem5::LinearSystem
Definition: linear_solver.hh:111
gem5::LinearSystem::toStr
std::string toStr() const
Definition: linear_solver.hh:124
gem5::LinearEquation::toStr
std::string toStr() const
Definition: linear_solver.hh:89
gem5::LinearEquation
This class describes a linear equation with constant coefficients.
Definition: linear_solver.hh:55
gem5::ArmISA::c
Bitfield< 29 > c
Definition: misc_types.hh:53
gem5::LinearEquation::LinearEquation
LinearEquation(unsigned unknowns)
Definition: linear_solver.hh:58
gem5::LinearSystem::matrix
std::vector< LinearEquation > matrix
Definition: linear_solver.hh:134
gem5::PowerISA::eq
Bitfield< 29 > eq
Definition: misc.hh:53
gem5::LinearEquation::operator[]
double & operator[](unsigned unkw)
Definition: linear_solver.hh:83
gem5::MipsISA::r
r
Definition: pra_constants.hh:98
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: decoder.cc:40
gem5::LinearEquation::operator*=
LinearEquation & operator*=(const double cnt)
Definition: linear_solver.hh:75
gem5::LinearEquation::cnt
unsigned cnt() const
Definition: linear_solver.hh:103

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