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https://github.com/Z3Prover/z3
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79 lines
2 KiB
C++
79 lines
2 KiB
C++
/*++
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Copyright (c) 2017 Microsoft Corporation
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Module Name:
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<name>
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Abstract:
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<abstract>
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Author:
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Lev Nachmanson (levnach)
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Revision History:
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--*/
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#include "math/lp/random_updater.h"
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#include "math/lp/static_matrix.h"
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#include "math/lp/lar_solver.h"
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#include "util/vector.h"
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namespace lp {
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random_updater::random_updater(
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lar_solver & lar_solver,
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const vector<unsigned> & column_indices) :
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m_lar_solver(lar_solver),
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m_range(100000) {
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m_var_set.resize(m_lar_solver.number_of_vars());
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for (unsigned j : column_indices)
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m_var_set.insert(j);
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TRACE("lar_solver_rand", tout << "size = " << m_var_set.size() << "\n";);
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}
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bool random_updater::shift_var(unsigned j) {
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SASSERT(!m_lar_solver.column_is_fixed(j) && !m_lar_solver.is_base(j));
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bool ret = m_lar_solver.get_int_solver()->shift_var(j, m_range);
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if (ret) {
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const auto & A = m_lar_solver.A_r();
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for (const auto& c : A.m_columns[j]) {
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m_var_set.erase(m_lar_solver.r_basis()[c.var()]);
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}
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}
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return ret;
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}
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void random_updater::update() {
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auto columns = m_var_set.index(); // m_var_set is going to change during the loop
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for (auto j : columns) {
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if (!m_var_set.contains(j)) {
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TRACE("lar_solver_rand", tout << "skipped " << j << "\n";);
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continue;
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}
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if (!m_lar_solver.is_base(j)) {
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shift_var(j);
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} else {
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unsigned row_index = m_lar_solver.r_heading()[j];
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for (auto & row_c : m_lar_solver.get_row(row_index)) {
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unsigned cj = row_c.var();
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if (!m_lar_solver.is_base(cj) &&
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!m_lar_solver.column_is_fixed(cj)
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&&
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shift_var(cj)
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) {
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break; // done with the basic var j
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}
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}
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}
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}
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TRACE("lar_solver_rand", tout << "m_var_set.size() = " << m_var_set.size() << "\n";);
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}
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}
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