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add implementation and toggleable param for splitting frugal + choosing deepest cubes only

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This commit is contained in:
Ilana Shapiro 2025-08-24 17:24:44 -07:00
parent 05e8c2e713
commit 9bf74b5d2b
3 changed files with 89 additions and 15 deletions
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3
src/params/smt_parallel_params.pyg
View file

@ -11,4 +11,7 @@ def_module_params('smt_parallel',
('share_units_initial_only', BOOL, False, 'share only initial Boolean atoms as units'),
('cube_initial_only', BOOL, False, 'cube only on initial Boolean atoms'),
('max_cube_size', UINT, 20, 'maximum size of a cube to share'),
('max_greedy_cubes', UINT, 1000, 'maximum number of cube to greedily share before switching to frugal'),
('num_split_lits', UINT, 2, 'how many literals, k, we split on to create 2^k cubes'),
('frugal_deepest_cube_only', BOOL, False, 'only apply frugal cube strategy, and only on a deepest (biggest) cube from the batch manager'),
))

80
src/smt/smt_parallel.cpp
View file

@ -137,6 +137,8 @@ namespace smt {
m_config.m_share_units_initial_only = pp.share_units_initial_only();
m_config.m_cube_initial_only = pp.cube_initial_only();
m_config.m_max_conflict_mul = pp.max_conflict_mul();
m_config.m_max_greedy_cubes = pp.max_greedy_cubes();
m_config.m_num_split_lits = pp.num_split_lits();
// don't share initial units
ctx->pop_to_base_lvl();
@ -272,13 +274,29 @@ namespace smt {
void parallel::batch_manager::get_cubes(ast_translation& g2l, vector<expr_ref_vector>& cubes) {
std::scoped_lock lock(mux);
if (m_cubes.size() == 1 && m_cubes[0].size() == 0) {
if (m_cubes.size() == 1 && m_cubes[0].empty()) {
// special initialization: the first cube is emtpy, have the worker work on an empty cube.
cubes.push_back(expr_ref_vector(g2l.to()));
return;
}
for (unsigned i = 0; i < std::min(m_max_batch_size / p.num_threads, (unsigned)m_cubes.size()) && !m_cubes.empty(); ++i) {
if (m_config.m_frugal_deepest_cube_only) {
// get the deepest set of cubes
auto& deepest_cubes = m_cubes_depth_sets.rbegin()->second;
unsigned idx = rand() % deepest_cubes.size();
auto& cube = deepest_cubes[idx]; // get a random cube from the deepest set
expr_ref_vector l_cube(g2l.to());
for (auto& e : cube) {
l_cube.push_back(g2l(e));
}
cubes.push_back(l_cube);
deepest_cubes.erase(deepest_cubes.begin() + idx); // remove the cube from the set
if (deepest_cubes.empty())
m_cubes_depth_sets.erase(m_cubes_depth_sets.size() - 1);
} else {
auto& cube = m_cubes.back();
expr_ref_vector l_cube(g2l.to());
for (auto& e : cube) {
@ -288,6 +306,7 @@ namespace smt {
m_cubes.pop_back();
}
}
}
void parallel::batch_manager::set_sat(ast_translation& l2g, model& m) {
std::scoped_lock lock(mux);
@ -341,7 +360,7 @@ namespace smt {
return l_undef; // the main context was cancelled, so we return undef.
switch (m_state) {
case state::is_running: // batch manager is still running, but all threads have processed their cubes, which means all cubes were unsat
if (!m_cubes.empty())
if (!m_cubes.empty() || (m_config.m_frugal_deepest_cube_only && !m_cubes_depth_sets.empty()))
throw default_exception("inconsistent end state");
if (!p.m_assumptions_used.empty()) {
// collect unsat core from assumptions used, if any --> case when all cubes were unsat, but depend on nonempty asms, so we need to add these asms to final unsat core
@ -439,9 +458,36 @@ namespace smt {
}
};
// apply the frugal strategy to ALL incoming worker cubes, but save in the deepest cube data structure
auto add_split_atom_deepest_cubes = [&](expr* atom) {
for (auto& c : C_worker) {
expr_ref_vector g_cube(l2g.to());
for (auto& atom : c)
g_cube.push_back(l2g(atom));
if (g_cube.size() >= m_config.m_max_cube_size) // we already added this before!! we just need to add the splits now
continue;
// add depth set d+1 if it doesn't exist yet
unsigned d = g_cube.size();
if (m_cubes_depth_sets.find(d + 1) == m_cubes_depth_sets.end())
m_cubes_depth_sets[d + 1] = vector<expr_ref_vector>();
// split on the negative atom
m_cubes_depth_sets[d + 1].push_back(g_cube);
m_cubes_depth_sets[d + 1].back().push_back(m.mk_not(atom));
// need to split on the positive atom too
g_cube.push_back(atom);
m_cubes_depth_sets[d + 1].push_back(g_cube);
m_stats.m_num_cubes += 2;
m_stats.m_max_cube_size = std::max(m_stats.m_max_cube_size, d + 1);
}
};
std::scoped_lock lock(mux);
unsigned max_cubes = 1000;
bool greedy_mode = (m_cubes.size() <= max_cubes) && !m_config.m_frugal_cube_only;
unsigned max_greedy_cubes = 1000;
bool greedy_mode = (m_cubes.size() <= max_greedy_cubes) && !m_config.m_frugal_cube_only && !m_config.m_frugal_deepest_cube_only;
unsigned a_worker_start_idx = 0;
//
@ -455,7 +501,7 @@ namespace smt {
m_split_atoms.push_back(g_atom);
add_split_atom(g_atom, 0); // split all *existing* cubes
if (m_cubes.size() > max_cubes) {
if (m_cubes.size() > max_greedy_cubes) {
greedy_mode = false;
++a_worker_start_idx; // start frugal from here
break;
@ -470,16 +516,26 @@ namespace smt {
expr_ref_vector g_cube(l2g.to());
for (auto& atom : c)
g_cube.push_back(l2g(atom));
unsigned start = m_cubes.size(); // update start after adding each cube so we only process the current cube being added
if (m_config.m_frugal_deepest_cube_only) {
// need to add the depth set if it doesn't exist yet
if (m_cubes_depth_sets.find(g_cube.size()) == m_cubes_depth_sets.end()) {
m_cubes_depth_sets[g_cube.size()] = vector<expr_ref_vector>();
}
m_cubes_depth_sets[g_cube.size()].push_back(g_cube);
m_stats.m_num_cubes += 1;
m_stats.m_max_cube_size = std::max(m_stats.m_max_cube_size, g_cube.size());
} else {
m_cubes.push_back(g_cube);
}
if (greedy_mode) {
// Split new cube on all existing m_split_atoms not in it
for (auto g_atom : m_split_atoms) {
if (!atom_in_cube(g_cube, g_atom)) {
add_split_atom(g_atom, start);
if (m_cubes.size() > max_cubes) {
if (m_cubes.size() > max_greedy_cubes) {
greedy_mode = false;
break;
}
@ -494,10 +550,14 @@ namespace smt {
expr_ref g_atom(l2g(A_worker[i]), l2g.to());
if (!m_split_atoms.contains(g_atom))
m_split_atoms.push_back(g_atom);
if (m_config.m_frugal_deepest_cube_only) {
add_split_atom_deepest_cubes(g_atom);
} else {
add_split_atom(g_atom, initial_m_cubes_size);
}
}
}
}
expr_ref_vector parallel::worker::get_split_atoms() {
#if false
@ -548,11 +608,17 @@ namespace smt {
m_state = state::is_running;
m_cubes.reset();
m_cubes.push_back(expr_ref_vector(m)); // push empty cube
if (m_config.m_frugal_deepest_cube_only) {
m_cubes_depth_sets.clear();
}
m_split_atoms.reset();
smt_parallel_params sp(p.ctx.m_params);
m_config.m_max_cube_size = sp.max_cube_size();
m_config.m_frugal_cube_only = sp.frugal_cube_only();
m_config.m_never_cube = sp.never_cube();
m_config.m_frugal_deepest_cube_only = sp.frugal_deepest_cube_only();
}
void parallel::batch_manager::collect_statistics(::statistics& st) const {

5
src/smt/smt_parallel.h
View file

@ -20,6 +20,7 @@ Revision History:
#include "smt/smt_context.h"
#include <thread>
#include <map>
namespace smt {
@ -49,6 +50,7 @@ namespace smt {
unsigned m_max_cube_size = 20;
bool m_frugal_cube_only = false;
bool m_never_cube = false;
bool m_frugal_deepest_cube_only = false;
};
struct stats {
unsigned m_max_cube_size = 0;
@ -63,6 +65,7 @@ namespace smt {
stats m_stats;
expr_ref_vector m_split_atoms; // atoms to split on
vector<expr_ref_vector> m_cubes;
std::map<unsigned, vector<expr_ref_vector>> m_cubes_depth_sets; // map<vec<cube>> contains sets of cubes, key is depth/size of cubes in the set
unsigned m_max_batch_size = 10;
unsigned m_exception_code = 0;
std::string m_exception_msg;
@ -120,6 +123,8 @@ namespace smt {
double m_max_conflict_mul = 1.5;
bool m_share_units_initial_only = false;
bool m_cube_initial_only = false;
bool m_max_greedy_cubes = 1000;
unsigned m_num_split_lits = 2;
};
unsigned id; // unique identifier for the worker