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limit the size of expressions in Grobner

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2019-12-16 11:24:14 -10:00
parent 7ddcfcafad
commit 26956cafb0
3 changed files with 29 additions and 20 deletions
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33
src/math/lp/nla_grobner.cpp
View file

@ -27,7 +27,7 @@ grobner::grobner(core *c, intervals *s)
m_gc(m_nex_creator,
c->m_reslim,
c->m_nla_settings.grobner_eqs_threshold(),
c->m_nla_settings.grobner_superposed_expr_size_limit()
c->m_nla_settings.grobner_expr_size_limit()
),
m_look_for_fixed_vars_in_rows(false) {
std::function<void (lp::explanation const& e, std::ostream & out)> de;
@ -205,12 +205,19 @@ bool grobner_core::compute_basis_step() {
}
m_stats.m_compute_steps++;
simplify_using_to_superpose(*eq);
if (equation_is_too_complex(eq))
return false;
if (!canceled() && simplify_to_superpose_with_eq(eq)) {
TRACE("grobner", tout << "eq = "; display_equation(tout, *eq););
superpose(eq);
insert_to_superpose(eq);
simplify_m_to_simplify(eq);
TRACE("grobner", tout << "end of iteration:\n"; display(tout););
if (equation_is_too_complex(eq)) {
TRACE("grobner", display_equation(tout, *eq) << " is too complex: deleting it\n;";);
del_equation(eq);
} else {
insert_to_superpose(eq);
simplify_m_to_simplify(eq);
TRACE("grobner", tout << "end of iteration:\n"; display(tout););
}
}
return false;
}
@ -486,7 +493,9 @@ void grobner_core::simplify_target_monomials_sum_j(equation const& source, equat
bool grobner_core::simplify_source_target(equation const& source, equation& target) {
TRACE("grobner", tout << "simplifying: "; display_equation(tout, target); tout << "\nusing: "; display_equation(tout, source););
TRACE("grobner_d", tout << "simplifying: " << *(target.expr()) << " using " << *(source.expr()) << "\n";);
SASSERT(m_nex_creator.is_simplified(*source.expr()));
SASSERT(m_nex_creator.is_simplified(*source.expr()) && !equation_is_too_complex(&source));
if (equation_is_too_complex(&target))
return false;
SASSERT(m_nex_creator.is_simplified(*target.expr()));
if (target.expr()->is_scalar()) {
TRACE("grobner_d", tout << "no simplification\n";);
@ -514,7 +523,7 @@ bool grobner_core::simplify_source_target(equation const& source, equation& targ
}
void grobner_core::process_simplified_target(equation* target, ptr_buffer<equation>& to_remove) {
if (is_trivial(target)) {
if (is_trivial(target) || equation_is_too_complex(target)) {
to_remove.push_back(target);
} else if (m_changed_leading_term) {
insert_to_simplify(target);
@ -525,8 +534,7 @@ void grobner_core::process_simplified_target(equation* target, ptr_buffer<equati
bool grobner_core::simplify_to_superpose_with_eq(equation* eq) {
TRACE("grobner_d", tout << "eq->exp " << *(eq->expr()) << "\n";);
ptr_buffer<equation> to_insert;
SASSERT(!equation_is_too_complex(eq));
ptr_buffer<equation> to_remove;
ptr_buffer<equation> to_delete;
for (equation * target : m_to_superpose) {
@ -537,15 +545,14 @@ bool grobner_core::simplify_to_superpose_with_eq(equation* eq) {
if (simplify_source_target(*eq, *target)) {
process_simplified_target(target, to_remove);
}
if (is_trivial(target)) {
if (is_trivial(target)||equation_is_too_complex(target)) {
to_delete.push_back(target);
}
else {
SASSERT(m_nex_creator.is_simplified(*target->expr()));
}
}
for (equation* eq : to_insert)
insert_to_superpose(eq);
for (equation* eq : to_remove)
m_to_superpose.erase(eq);
for (equation* eq : to_delete)
@ -560,7 +567,7 @@ void grobner_core::simplify_m_to_simplify(equation* eq) {
TRACE("grobner_d", tout << "eq->exp " << *(eq->expr()) << "\n";);
ptr_buffer<equation> to_delete;
for (equation* target : m_to_simplify) {
if (simplify_source_target(*eq, *target) && is_trivial(target))
if (simplify_source_target(*eq, *target) && (is_trivial(target) || equation_is_too_complex(target)))
to_delete.push_back(target);
}
for (equation* eq : to_delete)
@ -613,7 +620,7 @@ void grobner_core::superpose(equation * eq1, equation * eq2) {
TRACE("grobner_d", tout << "eq1="; display_equation(tout, *eq1) << "eq2="; display_equation(tout, *eq2););
init_equation(eq, expr_superpose(eq1->expr(), eq2->expr(), ab, ac, b, c), m_dep_manager.mk_join(eq1->dep(), eq2->dep()));
if (m_nex_creator.gt(eq->expr(), eq1->expr()) || m_nex_creator.gt(eq->expr(), eq2->expr()) ||
eq->expr()->size() > m_superposed_exp_size_limit) {
equation_is_too_complex(eq)) {
TRACE("grobner", display_equation(tout, *eq) << " is too complex: deleting it\n;";);
del_equation(eq);
} else {

10
src/math/lp/nla_grobner.h
View file

@ -89,15 +89,15 @@ private:
bool m_changed_leading_term;
equation_set m_all_eqs;
unsigned m_grobner_eqs_threshold;
unsigned m_superposed_exp_size_limit;
unsigned m_expr_size_limit;
public:
grobner_core(nex_creator& nc, reslimit& lim, unsigned eqs_threshold, unsigned superposed_expr_size_limit) :
grobner_core(nex_creator& nc, reslimit& lim, unsigned eqs_threshold, unsigned expr_size_limit) :
m_nex_creator(nc),
m_limit(lim),
m_dep_manager(m_val_manager, m_alloc),
m_changed_leading_term(false),
m_grobner_eqs_threshold(eqs_threshold),
m_superposed_exp_size_limit(superposed_expr_size_limit)
m_expr_size_limit(expr_size_limit)
{}
~grobner_core();
@ -159,7 +159,9 @@ private:
std::ostream& print_stats(std::ostream&) const;
std::ostream& display_dependency(std::ostream& out, common::ci_dependency*) const;
bool equation_is_too_complex(const equation* eq) const {
return eq->expr()->size() > m_expr_size_limit;
}
#ifdef Z3DEBUG
bool test_find_b_c(const nex* ab, const nex* ac, const nex_mul* b, const nex_mul* c);
bool test_find_b(const nex* ab, const nex_mul* b);

6
src/math/lp/nla_settings.h
View file

@ -32,7 +32,7 @@ class nla_settings {
unsigned m_grobner_frequency;
unsigned m_grobner_eqs_threshold;
unsigned m_grobner_row_length_limit;
unsigned m_grobner_superposed_expr_size_limit;
unsigned m_grobner_expr_size_limit;
public:
nla_settings() : m_run_order(true),
@ -44,7 +44,7 @@ public:
m_grobner_frequency(5),
m_grobner_eqs_threshold(512),
m_grobner_row_length_limit(10),
m_grobner_superposed_expr_size_limit(50)
m_grobner_expr_size_limit(50)
{}
unsigned grobner_eqs_threshold() const { return m_grobner_eqs_threshold; }
@ -70,6 +70,6 @@ public:
unsigned grobner_frequency() const { return m_grobner_frequency; }
unsigned& grobner_frequency() { return m_grobner_frequency; }
unsigned grobner_row_length_limit() const { return m_grobner_row_length_limit; }
unsigned grobner_superposed_expr_size_limit() const { return m_grobner_superposed_expr_size_limit; }
unsigned grobner_expr_size_limit() const { return m_grobner_expr_size_limit; }
};
}