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runs a simple test

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This commit is contained in:
Lev Nachmanson 2023-09-13 08:12:00 -07:00
parent c050af922f
commit c309d52283
11 changed files with 291 additions and 112 deletions
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74
src/math/lp/monomial_bounds.cpp
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@ -261,6 +261,7 @@ namespace nla {
void monomial_bounds::unit_propagate() {
for (lpvar v : c().m_monics_with_changed_bounds)
unit_propagate(c().emons()[v]);
c().m_monics_with_changed_bounds.clear();
}
void monomial_bounds::unit_propagate(monic const& m) {
@ -268,68 +269,61 @@ namespace nla {
if (m_propagated[m.var()])
return;
if (!is_linear(m))
lpvar non_fixed = null_lpvar, zero_var = null_lpvar;
if (!is_linear(m, zero_var, non_fixed))
return;
c().trail().push(set_bitvector_trail(m_propagated, m.var()));
rational k = fixed_var_product(m);
new_lemma lemma(c(), "fixed-values");
if (k == 0) {
for (auto v : m) {
if (c().var_is_fixed(v) && c().val(v).is_zero()) {
lemma.explain_fixed(v);
break;
}
}
if (zero_var != null_lpvar) {
new_lemma lemma(c(), "fixed-values");
lemma.explain_fixed(zero_var);
lemma += ineq(m.var(), lp::lconstraint_kind::EQ, 0);
}
else {
rational k = rational(1);
for (auto v : m)
if (c().var_is_fixed(v))
if (v != non_fixed) {
k *= c().lra.get_column_value(v).x;
if (k.is_big()) return;
}
new_lemma lemma(c(), "fixed-values");
for (auto v : m)
if (v != non_fixed)
lemma.explain_fixed(v);
lpvar w = non_fixed_var(m);
if (w != null_lpvar) {
if (non_fixed != null_lpvar) {
lp::lar_term term;
term.add_var(m.var());
term.add_monomial(-k, w);
term.add_monomial(-k, non_fixed);
lemma += ineq(term, lp::lconstraint_kind::EQ, 0);
} else {
lemma += ineq(m.var(), lp::lconstraint_kind::EQ, k);
}
}
}
bool monomial_bounds::is_linear(monic const& m) {
unsigned non_fixed = 0;
// returns true iff (all variables are fixed,
// or all but one variable are fixed) and the bounds are not big,
// or at least one variable is fixed to zero.
bool monomial_bounds::is_linear(monic const& m, lpvar& zero_var, lpvar& non_fixed) {
zero_var = non_fixed = null_lpvar;
unsigned n_of_non_fixed = 0;
bool big_bound = false;
for (lpvar v : m) {
if (!c().var_is_fixed(v))
++non_fixed;
else if (c().val(v).is_zero())
if (!c().var_is_fixed(v)) {
n_of_non_fixed++;
non_fixed = v;
} else if (c().var_is_fixed_to_zero(v)) {
zero_var = v;
return true;
} else if (c().fixed_var_has_big_bound(v)) {
big_bound |= true;
}
}
return non_fixed <= 1;
return n_of_non_fixed <= 1 && !big_bound;
}
rational monomial_bounds::fixed_var_product(monic const& m) {
rational r(1);
for (lpvar v : m) {
if (c().var_is_fixed(v))
r *= c().lra.get_column_value(v).x;
}
return r;
}
lpvar monomial_bounds::non_fixed_var(monic const& m) {
for (lpvar v : m)
if (!c().var_is_fixed(v))
return v;
return null_lpvar;
}
}