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generate lemma for proportional_case_le

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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
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93
src/util/lp/nla_solver.cpp
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@ -1108,15 +1108,54 @@ struct solver::imp {
};
// 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) {
if (!(abs(vvr(j)) >= rational(1) || vvr(k).is_zero()))
bool lemma_for_proportional_factors_on_vars_ge(lpvar xy, lpvar x, lpvar y) {
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;
// the precondition holds
if (! (abs(vvr(i)) >= abs(vvr(k)))) {
SASSERT(false); // create here
return true;
const rational & _xy = vvr(xy);
if (abs(_xy) >= abs(_y))
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)));
}
return false;
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
// we derive a lemma from |x| <= 1 || y = 0 => |xy| <= |y|
@ -1137,26 +1176,44 @@ struct solver::imp {
const rational & _xy = vvr(xy);
if (abs(_xy) <= abs(_y))
return false;
// adding x != val(x);
// Here we just create the lemma.
lp::lar_term t;
t.add_coeff_var(rational(1), x);
m_lemma->push_back(ineq(lp::lconstraint_kind::NE, t, _x));
if (abs(_x) <= rational(1)) {
// add to lemma x < -1 || x > 1
t.add_coeff_var(rational(1), 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.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;
y_sign = -1;
m_lemma->push_back(ineq(lp::lconstraint_kind::GT, t, rational::zero()));
}
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.add_coeff_var(rational(xy_sign), xy);
t.add_coeff_var(rational(-y_sign), y);