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linear solver

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-05-14 17:10:01 -07:00
parent 17fcf79c04
commit 683ce27c8f
8 changed files with 264 additions and 42 deletions
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154
src/math/polysat/linear_solver.cpp
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@ -17,19 +17,155 @@ Author:
namespace polysat {
void linear_solver::push() {}
void linear_solver::pop(unsigned n) {}
void linear_solver::new_constraint(constraint& c) {}
void linear_solver::set_value(pvar v, rational const& value) {}
void linear_solver::set_bound(pvar v, rational const& lo, rational const& hi) {}
void linear_solver::activate_constraint(constraint& c) {}
void linear_solver::push() {
m_trail.push_back(trail_i::inc_level_i);
}
void linear_solver::pop(unsigned n) {
while (n > 0) {
switch (m_trail.back()) {
case trail_i::inc_level_i:
--n;
break;
case trail_i::add_var_i:
NOT_IMPLEMENTED_YET();
break;
case trail_i::set_bound_i: {
auto [v, sz] = m_rows.back();
sz2fixplex(sz).restore_bound();
m_rows.pop_back();
break;
}
case trail_i::set_value_i:
break;
case trail_i::add_row_i: {
auto [v, sz] = m_rows.back();
sz2fixplex(sz).del_row(v);
m_rows.pop_back();
break;
}
case trail_i::activate_constraint_i:
// not needed?
NOT_IMPLEMENTED_YET();
break;
default:
UNREACHABLE();
}
m_trail.pop_back();
}
}
fixplex_base& linear_solver::sz2fixplex(unsigned sz) {
fixplex_base* b = m_fix.get(sz, nullptr);
if (!b) {
switch (sz) {
case 64:
b = alloc(fixplex<uint64_ext>, s.m_lim);
break;
case 8:
case 16:
case 32:
case 128:
case 256:
default:
NOT_IMPLEMENTED_YET();
break;
}
m_fix.set(sz, b);
}
return *b;
}
void linear_solver::new_constraint(constraint& c) {
switch (c.kind()) {
case ckind_t::eq_t: {
//
// create the row c.p() - v == 0
// when equality is asserted, set range on v as v == 0 or v > 0.
//
pdd p = c.to_eq().p();
unsigned sz = p.power_of_2();
linearize(p);
var_t v = fresh_var(sz);
m_vars.push_back(v);
m_coeffs.push_back(rational::power_of_two(sz) - 1);
sz2fixplex(sz).add_row(v, m_vars.size(), m_vars.data(), m_coeffs.data());
m_rows.push_back(std::make_pair(v, sz));
m_trail.push_back(trail_i::add_row_i);
m_bool_var2row.setx(c.bvar(), v, UINT_MAX);
break;
}
case ckind_t::ule_t:
case ckind_t::bit_t:
break;
}
}
void linear_solver::activate_constraint(constraint& c) {
switch (c.kind()) {
case ckind_t::eq_t: {
var_t v = m_bool_var2row[c.bvar()];
pdd p = c.to_eq().p();
unsigned sz = p.power_of_2();
auto& fp = sz2fixplex(sz);
m_trail.push_back(trail_i::set_bound_i);
m_rows.push_back(std::make_pair(v, sz));
if (c.is_positive())
fp.set_bounds(v, rational::zero(), rational::zero());
else
fp.set_bounds(v, rational::one(), rational::power_of_two(sz) - 1);
break;
}
case ckind_t::ule_t:
case ckind_t::bit_t:
break;
}
}
void linear_solver::linearize(pdd const& p) {
unsigned sz = p.power_of_2();
m_vars.reset();
m_coeffs.reset();
for (auto const& m : p) {
m_vars.push_back(mono2var(sz, m.vars));
m_coeffs.push_back(m.coeff);
}
}
var_t linear_solver::mono2var(unsigned sz, unsigned_vector const& var) {
NOT_IMPLEMENTED_YET();
return 0;
}
var_t linear_solver::fresh_var(unsigned sz) {
NOT_IMPLEMENTED_YET();
return 0;
}
void linear_solver::set_value(pvar v, rational const& value) {
}
void linear_solver::set_bound(pvar v, rational const& lo, rational const& hi) {
unsigned sz = s.size(v);
auto& fp = sz2fixplex(sz);
m_trail.push_back(trail_i::set_bound_i);
m_rows.push_back(std::make_pair(v, sz));
fp.set_bounds(v, lo, hi);
}
// check integer modular feasibility under current bounds.
lbool linear_solver::check() { return l_undef; }
void linear_solver::unsat_core(unsigned_vector& deps) {}
lbool linear_solver::check() {
return l_undef;
}
void linear_solver::unsat_core(unsigned_vector& deps) {
}
// current value assigned to (linear) variable according to tableau.
rational linear_solver::value(pvar v) { return rational(0); }
rational linear_solver::value(pvar v) {
return rational(0);
}
};