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gauss jordan

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-05-09 16:33:05 -07:00
parent 361888f299
commit ad2445e423
8 changed files with 183 additions and 9 deletions
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4
src/math/simplex/simplex.cpp
View file

@ -18,6 +18,7 @@ Notes:
--*/
#include "math/simplex/simplex.h"
#include "math/simplex/sparse_matrix_ops.h"
#include "math/simplex/sparse_matrix_def.h"
#include "math/simplex/simplex_def.h"
#include "util/rational.h"
@ -36,6 +37,9 @@ namespace simplex {
}
}
void gauss_jordan(sparse_matrix<mpq_ext>& M) {
sparse_matrix_ops::gauss_jordan(M);
}
void ensure_rational_solution(simplex<mpq_ext>& S) {
rational delta(1);

2
src/math/simplex/simplex.h
View file

@ -200,5 +200,7 @@ namespace simplex {
};
void ensure_rational_solution(simplex<mpq_ext>& s);
void gauss_jordan(sparse_matrix<mpq_ext>& s);
};

69
src/math/simplex/sparse_matrix.h
View file

@ -201,8 +201,22 @@ namespace simplex {
row_iterator row_begin(row const& r) { return row_iterator(m_rows[r.id()], true); }
row_iterator row_end(row const& r) { return row_iterator(m_rows[r.id()], false); }
class row_vars {
friend class sparse_matrix;
sparse_matrix& s;
row r;
row_vars(sparse_matrix& s, row r): s(s), r(r) {}
public:
row_iterator begin() { return s.row_begin(r); }
row_iterator end() { return s.row_end(r); }
};
row_vars get_row(row r) { return row_vars(*this, r); }
unsigned column_size(var_t v) const { return m_columns[v].size(); }
unsigned num_vars() const { return m_columns.size(); }
class col_iterator {
friend class sparse_matrix;
unsigned m_curr;
@ -228,15 +242,16 @@ namespace simplex {
--m_col.m_refs;
}
row get_row() {
row get_row() const {
return row(m_col.m_entries[m_curr].m_row_id);
}
row_entry const& get_row_entry() {
row_entry const& get_row_entry() const {
col_entry const& c = m_col.m_entries[m_curr];
int row_id = c.m_row_id;
return m_rows[row_id].m_entries[c.m_row_idx];
}
std::pair<row, row_entry const*> operator*() { return std::make_pair(get_row(), &get_row_entry()); }
col_iterator & operator++() { ++m_curr; move_to_used(); return *this; }
col_iterator operator++(int) { col_iterator tmp = *this; ++*this; return tmp; }
bool operator==(col_iterator const & it) const { return m_curr == it.m_curr; }
@ -246,10 +261,58 @@ namespace simplex {
col_iterator col_begin(int v) const { return col_iterator(m_columns[v], m_rows, true); }
col_iterator col_end(int v) const { return col_iterator(m_columns[v], m_rows, false); }
class var_rows {
friend class sparse_matrix;
sparse_matrix& s;
int v;
var_rows(sparse_matrix& s, int v):s(s), v(v) {}
public:
col_iterator begin() { return s.col_begin(v); }
col_iterator end() { return s.col_end(v); }
};
var_rows get_rows(int v) { return var_rows(*this, v); }
class all_row_iterator {
friend class sparse_matrix;
unsigned m_curr;
vector<_row> const& m_rows;
void move_to_next() {
while (m_curr < m_rows.size() && m_rows[m_curr].size() == 0) {
std::cout << "size is 0 for " << m_curr << "\n";
++m_curr;
}
}
public:
all_row_iterator(unsigned curr, vector<_row> const& rows): m_curr(curr), m_rows(rows) {
move_to_next();
}
row operator*() { return row(m_curr); }
all_row_iterator & operator++() { m_curr++; move_to_next(); return *this; }
all_row_iterator operator++(int) { all_row_iterator tmp = *this; ++*this; return tmp; }
bool operator==(all_row_iterator const& it) const { return m_curr == it.m_curr; }
bool operator!=(all_row_iterator const& it) const { return m_curr != it.m_curr; }
};
class all_rows {
friend class sparse_matrix;
sparse_matrix& s;
all_rows(sparse_matrix& s): s(s) {}
public:
all_row_iterator begin() { return all_row_iterator(0, s.m_rows); }
all_row_iterator end() { return all_row_iterator(s.m_rows.size(), s.m_rows); }
};
all_rows get_rows() { return all_rows(*this); }
void display(std::ostream& out);
void display_row(std::ostream& out, row const& r);
bool well_formed() const;
manager& get_manager() { return m; }
void collect_statistics(::statistics & st) const;
};

68
src/math/simplex/sparse_matrix_ops.h Normal file
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@ -0,0 +1,68 @@
/*++
Copyright (c) 2014 Microsoft Corporation
Module Name:
sparse_matrix_ops.h
Abstract:
Author:
Nikolaj Bjorner (nbjorner) 2014-01-15
Notes:
--*/
#pragma once
#include "math/simplex/sparse_matrix.h"
#include "util/rational.h"
namespace simplex {
class sparse_matrix_ops {
public:
static void gauss_jordan(sparse_matrix<mpq_ext>& M) {
mpq_ext::numeral coeff;
vector<unsigned> c, d;
unsigned m = M.num_vars();
for (unsigned v = 0; v < m; ++v)
c.push_back(0);
for (auto const& row : M.get_rows()) {
// scan for non-zero variable in row
bool found = false;
for (auto const& [coeff1, v] : M.get_row(row)) {
if (mpq_manager<false>::is_zero(coeff1))
continue;
found = true;
d.push_back(v);
c[v] = row.id() + 1;
// eliminate v from other rows.
for (auto const& [row2, row_entry2] : M.get_rows(v)) {
if (row.id() == row2.id())
continue;
if (row_entry2->m_coeff == 0)
continue;
M.get_manager().set(coeff, (- row_entry2->m_coeff / coeff1).to_mpq());
M.add(row2, coeff, row);
}
break;
}
if (!found)
d.push_back(0);
}
M.get_manager().del(coeff);
// TODO: do something with c and d
}
};
}