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cleanup

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Signed-off-by: Lev <levnach@hotmail.com>
This commit is contained in:
Lev 2018-10-15 19:15:37 -07:00 • committed by Lev Nachmanson
parent 40ea66ff70
commit 492abc1e57
1 changed files with 2 additions and 88 deletions
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90
src/util/lp/nla_solver.cpp
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@ -326,93 +326,6 @@ struct solver::imp {
return 2; // the sign of the variable is not defined return 2; // the sign of the variable is not defined
} }
// Return 0 if the monomial has to to have a zero value,
// -1 if the monomial has to be negative or zero
// 1 if positive or zero
// otherwise return 2 (2 is not a sign!)
// if strict is true then 0 is excluded
int get_mon_sign_zero(unsigned i_mon, bool & strict) {
int sign = 1;
strict = true;
const monomial m = m_monomials[i_mon];
for (lpvar j : m) {
int s = get_mon_sign_zero_var(j, strict);
if (s == 2)
return 2;
if (s == 0)
return 0;
sign *= s;
}
return sign;
}
/*
Here we use the following theorems
a) v1 = 0 or v2 = 0 iff v1*v2 = 0
b) (v1 > 0 and v2 > 0) or (v1 < 0 and v2 < 0) iff
v1 * v2 > 0
c) (v1 < 0 and v2 > 0) or (v1 > 0 and v2 < 0) iff
v1 * v2 < 0
*/
bool basic_lemma_for_mon_zero(unsigned i_mon) {
m_expl->clear();
const auto mon = m_monomials[i_mon];
const rational & mon_val = m_lar_solver.get_column_value_rational(mon.var());
bool strict;
int sign = get_mon_sign_zero(i_mon, strict);
lp::lconstraint_kind kind;
rational rs(0);
switch(sign) {
case 0:
SASSERT(!mon_val.is_zero());
kind = lp::lconstraint_kind::EQ;
break;
case 1:
if (strict)
rs = rational(1);
if (mon_val >= rs)
return false;
kind = lp::lconstraint_kind::GE;
break;
case -1:
if (strict)
rs = rational(-1);
if (mon_val <= rs)
return false;
kind = lp::lconstraint_kind::LE;
break;
default:
if (mon_val.is_zero() && var_is_fixed_to_zero(mon.var())) {
create_lemma_one_of_the_factors_is_zero(mon);
TRACE("nla_solver", print_explanation_and_lemma(tout););
return true;
}
return false;
}
mk_ineq(m_monomials[i_mon].var(), kind, rs);
TRACE("nla_solver", print_explanation_and_lemma(tout););
return true;
}
void create_lemma_one_of_the_factors_is_zero(const monomial& m) {
lpci lci, uci;
rational b;
bool is_strict;
m_lar_solver.has_lower_bound(m.var(), lci, b, is_strict);
SASSERT(b.is_zero() && !is_strict);
m_lar_solver.has_upper_bound(m.var(), uci, b, is_strict);
SASSERT(b.is_zero() && !is_strict);
m_expl->clear();
m_expl->push_justification(lci);
m_expl->push_justification(uci);
m_lemma->clear();
for (auto j : m) {
mk_ineq(j, lp::lconstraint_kind::EQ, rational::zero());
}
}
bool var_is_fixed_to_zero(lpvar j) const { bool var_is_fixed_to_zero(lpvar j) const {
return return
m_lar_solver.column_has_upper_bound(j) && m_lar_solver.column_has_upper_bound(j) &&
@ -1328,8 +1241,9 @@ struct solver::imp {
init_search(); init_search();
if (basic_lemma(to_refine)) if (basic_lemma(to_refine)) {
return l_false; return l_false;
}
return l_undef; return l_undef;
} }