mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-07-18 02:16:40 +00:00
Code Activity

remove watch, hoist orbit to track used variables

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-01-02 00:39:50 -08:00
parent 1d0572354b
commit c1032c3403
6 changed files with 46 additions and 117 deletions
Download patch file Download diff file Expand all files Collapse all files

95
src/math/grobner/pdd_solver.cpp
View file

@ -47,18 +47,6 @@ namespace dd {
- add a to S
- simplify A using a
Apply a watch list to filter out relevant elements of S
Index leading_term_watch: Var -> Equation*
Only need to simplify equations that contain eliminated variable.
The watch list can be used to index into equations that are useful to simplify.
A Bloom filter on leading term could further speed up test whether reduction applies.
For p in A:
populate watch list by maxvar(p) |-> p
For p in S:
do not occur in watch list
- the variable ordering should be chosen from a candidate model M,
in a way that is compatible with weights that draw on the number of occurrences
in polynomials with violated evaluations and with the maximal slack (degree of freedom).
@ -67,12 +55,6 @@ namespace dd {
slack is computed from interval assignments to variables, and is an interval in which x can possibly move
(an over-approximation).
The alternative version maintains the following invariant:
- polynomials not in the watch list cannot be simplified using a
Justification:
- elements in S have no variables watched
- elements in A are always reduced modulo all variables above the current x_i.
*/
@ -99,7 +81,6 @@ namespace dd {
DEBUG_CODE(invariant(););
}
catch (pdd_manager::mem_out) {
m_watch.reset();
IF_VERBOSE(2, verbose_stream() << "mem-out\n");
// don't reduce further
}
@ -161,8 +142,7 @@ namespace dd {
/*
Use the given equation to simplify equations in set
*/
void solver::simplify_using(equation_vector& set, equation const& eq) {
void solver::simplify_using(equation_vector& set, equation const& eq) {
struct scoped_update {
equation_vector& set;
unsigned i, j, sz;
@ -195,9 +175,8 @@ namespace dd {
else if (simplified && changed_leading_term) {
SASSERT(target.state() == processed);
push_equation(to_simplify, target);
if (!m_watch.empty()) {
if (!m_var2level.empty()) {
m_levelp1 = std::max(m_var2level[target.poly().var()]+1, m_levelp1);
add_to_watch(target);
}
}
else {
@ -276,7 +255,6 @@ namespace dd {
if (!e) return false;
scoped_process sd(*this, e);
equation& eq = *e;
SASSERT(!m_watch[eq.poly().var()].contains(e));
SASSERT(eq.state() == to_simplify);
simplify_using(eq, m_processed);
if (is_trivial(eq)) { sd.e = nullptr; retire(e); return true; }
@ -286,7 +264,7 @@ namespace dd {
if (done()) return false;
TRACE("dd.solver", display(tout << "eq = ", eq););
superpose(eq);
simplify_watch(eq);
simplify_using(m_to_simplify, eq);
if (done()) return false;
if (!m_too_complex) sd.done();
return true;
@ -300,58 +278,14 @@ namespace dd {
m_level2var[i] = l2v[i];
m_var2level[l2v[i]] = i;
}
m_watch.reset();
m_watch.reserve(m_level2var.size());
m_levelp1 = m_level2var.size();
for (equation* eq : m_to_simplify) add_to_watch(*eq);
}
void solver::add_to_watch(equation& eq) {
SASSERT(eq.state() == to_simplify);
pdd const& p = eq.poly();
if (!p.is_val()) {
m_watch[p.var()].push_back(&eq);
}
}
void solver::simplify_watch(equation const& eq) {
unsigned v = eq.poly().var();
auto& watch = m_watch[v];
unsigned j = 0;
for (equation* _target : watch) {
equation& target = *_target;
SASSERT(target.state() == to_simplify);
SASSERT(target.poly().var() == v);
bool changed_leading_term = false;
if (!done()) {
try_simplify_using(target, eq, changed_leading_term);
}
if (is_trivial(target)) {
pop_equation(target);
retire(&target);
}
else if (is_conflict(target)) {
pop_equation(target);
set_conflict(target);
}
else if (target.poly().var() != v) {
// move to other watch list
m_watch[target.poly().var()].push_back(_target);
}
else {
// keep watching same variable
watch[j++] = _target;
}
}
watch.shrink(j);
}
solver::equation* solver::pick_next() {
while (m_levelp1 > 0) {
unsigned v = m_level2var[m_levelp1-1];
equation_vector const& watch = m_watch[v];
equation* eq = nullptr;
for (equation* curr : watch) {
for (equation* curr : m_to_simplify) {
pdd const& p = curr->poly();
if (curr->state() == to_simplify && p.var() == v) {
if (!eq || is_simpler(*curr, *eq))
@ -360,7 +294,6 @@ namespace dd {
}
if (eq) {
pop_equation(eq);
m_watch[eq->poly().var()].erase(eq);
return eq;
}
--m_levelp1;
@ -384,7 +317,6 @@ namespace dd {
m_processed.reset();
m_to_simplify.reset();
m_stats.reset();
m_watch.reset();
m_level2var.reset();
m_var2level.reset();
m_conflict = nullptr;
@ -398,9 +330,8 @@ namespace dd {
}
push_equation(to_simplify, eq);
if (!m_watch.empty()) {
if (!m_var2level.empty()) {
m_levelp1 = std::max(m_var2level[p.var()]+1, m_levelp1);
add_to_watch(*eq);
}
update_stats_max_degree_and_size(*eq);
}
@ -524,28 +455,12 @@ namespace dd {
// equations in to_simplify have correct indices
// they are labeled as non-processed
// their top-most variable is watched
i = 0;
for (auto* e : m_to_simplify) {
VERIFY(e->idx() == i);
VERIFY(e->state() == to_simplify);
pdd const& p = e->poly();
VERIFY(!p.is_val());
CTRACE("dd.solver", !m_watch.empty() && !m_watch[p.var()].contains(e),
display(tout << "not watched: ", *e) << "\n";);
VERIFY(m_watch.empty() || m_watch[p.var()].contains(e));
++i;
}
// the watch list consists of equations in to_simplify
// they watch the top most variable in poly
i = 0;
for (auto const& w : m_watch) {
for (equation* e : w) {
VERIFY(!e->poly().is_val());
VERIFY(e->poly().var() == i);
VERIFY(e->state() == to_simplify);
VERIFY(m_to_simplify.contains(e));
}
++i;
}
}