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univariate::find_min

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This commit is contained in:
Jakob Rath 2022-12-15 15:34:50 +01:00
parent 37536425f4
commit 31e0add966
3 changed files with 118 additions and 5 deletions
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34
src/math/polysat/univariate/univariate_solver.cpp
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@ -98,14 +98,14 @@ namespace polysat {
return mk_numeral(rational::zero());
}
else {
expr* e = mk_numeral(p.back());
expr* e = mk_numeral(p[0]);
expr* xpow = x;
for (unsigned i = p.size() - 1; i-- > 0; ) {
for (unsigned i = 1; i < p.size(); ++i) {
if (!p[i].is_zero()) {
expr* t = mk_poly_term(p[i], xpow);
e = bv->mk_bv_add(e, t);
}
if (i)
if (i + 1 < p.size())
xpow = bv->mk_bv_mul(xpow, x);
}
return e;
@ -205,6 +205,34 @@ namespace polysat {
return p.get_rational();
}
bool find_min(rational& val) override {
val = model();
push();
// try reducing val by setting bits to 0, starting at the msb.
for (unsigned k = bit_width; k-- > 0; ) {
if (!val.get_bit(k)) {
add_bit0(k, 0);
continue;
}
push();
add_bit0(k, 0);
lbool result = check();
if (result == l_true) {
SASSERT(model() < val);
val = model();
}
pop(1);
if (result == l_true)
add_bit0(k, 0);
else if (result == l_false)
add_bit1(k, 0);
else
return false;
}
pop(1);
return true;
}
std::ostream& display(std::ostream& out) const override {
return out << *s;
}

10
src/math/polysat/univariate/univariate_solver.h
View file

@ -41,9 +41,17 @@ namespace polysat {
virtual void pop(unsigned n) = 0;
virtual lbool check() = 0;
// Precondition: check() returned l_false
virtual dep_vector unsat_core() = 0;
// Precondition: check() returned l_true
virtual rational model() = 0;
// Precondition: check() returned l_true
// Returns false on resource out.
virtual bool find_min(rational& out_min) = 0;
virtual void add_ule(univariate const& lhs, univariate const& rhs, bool sign, dep_t dep) = 0;
virtual void add_umul_ovfl(univariate const& lhs, univariate const& rhs, bool sign, dep_t dep) = 0;
virtual void add_smul_ovfl(univariate const& lhs, univariate const& rhs, bool sign, dep_t dep) = 0;
@ -65,6 +73,8 @@ namespace polysat {
/// Assert i-th bit of x
virtual void add_bit(unsigned idx, bool sign, dep_t dep) = 0;
void add_bit0(unsigned idx, dep_t dep) { add_bit(idx, true, dep); }
void add_bit1(unsigned idx, dep_t dep) { add_bit(idx, false, dep); }
virtual std::ostream& display(std::ostream& out) const = 0;
};