mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-06-20 04:43:39 +00:00
Code Activity

generate lemma for proportional_case_le

Browse source 
Signed-off-by: Lev <levnach@hotmail.com>
This commit is contained in:
Lev 2018-09-27 10:19:34 -07:00 • committed by Lev Nachmanson
parent f8e4f5c5c6
commit 8350d8702f
1 changed files with 75 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

87
src/util/lp/nla_solver.cpp
View file

@ -1108,15 +1108,54 @@ struct solver::imp {
}; };
// we derive a lemma from |x| >= 1 || y = 0 => |xy| >= |y| // we derive a lemma from |x| >= 1 || y = 0 => |xy| >= |y|
bool lemma_for_proportional_factors_on_vars_ge(lpvar i, lpvar j, lpvar k) { bool lemma_for_proportional_factors_on_vars_ge(lpvar xy, lpvar x, lpvar y) {
if (!(abs(vvr(j)) >= rational(1) || vvr(k).is_zero())) TRACE("nla_solver",
tout << "xy=";
print_var(xy, tout);
tout << "x=";
print_var(x, tout);
tout << "y=";
print_var(y, tout););
const rational & _x = vvr(x);
const rational & _y = vvr(y);
if (!(abs(_x) >= rational(1) || _y.is_zero()))
return false; return false;
// the precondition holds // the precondition holds
if (! (abs(vvr(i)) >= abs(vvr(k)))) { const rational & _xy = vvr(xy);
SASSERT(false); // create here if (abs(_xy) >= abs(_y))
return true;
}
return false; return false;
// adding negation of x >= 1 or the negation of x <= -1
lp::lar_term t;
t.add_coeff_var(rational(1), x);
if (_x >= rational(1)) {
m_lemma->push_back(ineq(lp::lconstraint_kind::LT, t, rational(1)));
} else {
SASSERT(_x <= -rational(1));
m_lemma->push_back(ineq(lp::lconstraint_kind::GT, t, -rational(1)));
}
t.clear();
t.add_coeff_var(rational(1), y);
int y_sign;
if (_y.is_pos()) {
y_sign = 1;
m_lemma->push_back(ineq(lp::lconstraint_kind::LE, t, rational::zero()));
} else if (_y.is_neg()) {
y_sign = -1;
m_lemma->push_back(ineq(lp::lconstraint_kind::GE, t, rational::zero()));
} else {
SASSERT(_y.is_zero());
y_sign = 1;
m_lemma->push_back(ineq(lp::lconstraint_kind::NE, t, rational::zero()));
}
int xy_sign = _xy.is_pos()? 1: -1;
t.clear(); // abs(xy) - abs(y) <= 0
t.add_coeff_var(rational(xy_sign), xy);
t.add_coeff_var(rational(-y_sign), y);
m_lemma->push_back(ineq(lp::lconstraint_kind::LE, t, rational::zero()));
TRACE("nla_solver", tout<< "lemma: ";print_lemma(*m_lemma, tout););
return true;
} }
// here xy // here xy
// we derive a lemma from |x| <= 1 || y = 0 => |xy| <= |y| // we derive a lemma from |x| <= 1 || y = 0 => |xy| <= |y|
@ -1137,10 +1176,20 @@ struct solver::imp {
const rational & _xy = vvr(xy); const rational & _xy = vvr(xy);
if (abs(_xy) <= abs(_y)) if (abs(_xy) <= abs(_y))
return false; return false;
// adding x != val(x); // Here we just create the lemma.
lp::lar_term t; lp::lar_term t;
if (abs(_x) <= rational(1)) {
// add to lemma x < -1 || x > 1
t.add_coeff_var(rational(1), x); t.add_coeff_var(rational(1), x);
m_lemma->push_back(ineq(lp::lconstraint_kind::NE, t, _x)); m_lemma->push_back(ineq(lp::lconstraint_kind::LT, t, -rational(1)));
m_lemma->push_back(ineq(lp::lconstraint_kind::GT, t, rational(1)));
} else {
lp_assert(_y.is_zero() && t.is_empty());
// add to lemma y != 0
t.add_coeff_var(rational(1), y);
m_lemma->push_back(ineq(lp::lconstraint_kind::NE, t, rational::zero()));
}
t.clear(); t.clear();
t.add_coeff_var(rational(1), y); t.add_coeff_var(rational(1), y);
@ -1148,15 +1197,23 @@ struct solver::imp {
if (_y.is_pos()) { if (_y.is_pos()) {
y_sign = 1; y_sign = 1;
m_lemma->push_back(ineq(lp::lconstraint_kind::LE, t, rational::zero())); m_lemma->push_back(ineq(lp::lconstraint_kind::LE, t, rational::zero()));
} else if (_y.is_neg()) {
y_sign = -1;
m_lemma->push_back(ineq(lp::lconstraint_kind::GE, t, rational::zero()));
} else { } else {
SASSERT(_y.is_zero()); y_sign = -1;
y_sign = 1; m_lemma->push_back(ineq(lp::lconstraint_kind::GT, t, rational::zero()));
m_lemma->push_back(ineq(lp::lconstraint_kind::NE, t, rational::zero()));
} }
int xy_sign = _xy.is_pos()? 1: -1;
t.clear();
t.add_coeff_var(rational(1), xy);
int xy_sign;
if (_y.is_pos()) {
xy_sign = 1;
m_lemma->push_back(ineq(lp::lconstraint_kind::LE, t, rational::zero()));
} else {
xy_sign = -1;
m_lemma->push_back(ineq(lp::lconstraint_kind::GT, t, rational::zero()));
}
t.clear(); // abs(xy) - abs(y) <= 0 t.clear(); // abs(xy) - abs(y) <= 0
t.add_coeff_var(rational(xy_sign), xy); t.add_coeff_var(rational(xy_sign), xy);
t.add_coeff_var(rational(-y_sign), y); t.add_coeff_var(rational(-y_sign), y);