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Lev Nachmanson 2025-08-12 08:59:20 -07:00
parent 4be2fc416f
commit 3c9c7105d3
5 changed files with 293 additions and 74 deletions
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1
src/nlsat/CMakeLists.txt
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@ -4,6 +4,7 @@ z3_add_component(nlsat
nlsat_evaluator.cpp
nlsat_explain.cpp
nlsat_interval_set.cpp
levelwise.cpp
nlsat_simplify.cpp
nlsat_solver.cpp
nlsat_types.cpp

290
src/nlsat/levelwise.cpp Normal file
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@ -0,0 +1,290 @@
#include "levelwise.h"
#include <vector>
#include <string>
#include <sstream>
namespace nlsat {
// Context for property propagation (e.g., which case of rule 4.2 applies)
enum class property_mapping_case : unsigned {
case1 = 0,
case2 = 1,
case3 = 2,
};
/**
* Properties for indexed roots, in the order specified by the levelwise paper.
* The order is important for the algorithm and must match the paper exactly.
*/
enum class polynom_property : unsigned {
ir_ord, // ir_ord(≼, s) for all ≼ for roots of level i and s ∈ Ri−1
an_del, // an_del(p) for all p of level i
non_null, // non_null(p) for all p of level i
ord_inv_reducible, // ord_inv(p) for all reducible p of level i
ord_inv_irreducible, // ord_inv(p) for all irreducible p of level i
sgn_inv_reducible, // sgn_inv(p) for all reducible p of level i
sgn_inv_irreducible, // sgn_inv(p) for all irreducible p of level i
connected, // connected(i)
an_sub, // an_sub(i)
sample, // sample(s) for all s ∈ Ri of level i
repr, // repr(I, s) for all I of level i and s ∈ ...
holds, // marker for "goal holds" (terminal)
_count // always last: number of properties
};
// Utility: property to string (for debugging, logging, etc.)
inline const char* to_string(polynom_property prop) {
switch (prop) {
case polynom_property::ir_ord: return "ir_ord";
case polynom_property::an_del: return "an_del";
case polynom_property::non_null: return "non_null";
case polynom_property::ord_inv_reducible: return "ord_inv_reducible";
case polynom_property::ord_inv_irreducible: return "ord_inv_irreducible";
case polynom_property::sgn_inv_reducible: return "sgn_inv_reducible";
case polynom_property::sgn_inv_irreducible: return "sgn_inv_irreducible";
case polynom_property::connected: return "connected";
case polynom_property::an_sub: return "an_sub";
case polynom_property::sample: return "sample";
case polynom_property::repr: return "repr";
case polynom_property::holds: return "holds";
default: return "?";
}
}
// A single property instance ("fact") subject.
// Note: Not all fields are used by every property; unused fields are left at defaults.
struct property_inst {
polynom_property prop;
// Optional subject parameters
poly* p = nullptr; // for properties about a polynomial p
var y = -1; // variable (e.g., indexed root variable)
unsigned i = 0; // level/index (paper's i)
unsigned s_idx = 0; // index for "s ∈ R_i" (sample/root index), if applicable
unsigned I_idx = 0; // index for interval I (for repr), if applicable
unsigned ord_id = 0; // identifier for an indexed root ordering ≼, if applicable
// Convenience builders
static property_inst of(poly* p, polynom_property prop, unsigned level) {
property_inst r{prop}; r.p = p; r.i = level; return r;
}
static property_inst at_level(polynom_property prop, unsigned level) {
property_inst r{prop}; r.i = level; return r;
}
static property_inst sample_at(unsigned s_idx, unsigned level) {
property_inst r{polynom_property::sample}; r.s_idx = s_idx; r.i = level; return r;
}
static property_inst repr_of(unsigned I_idx, unsigned s_idx, unsigned level) {
property_inst r{polynom_property::repr}; r.I_idx = I_idx; r.s_idx = s_idx; r.i = level; return r;
}
// Display
std::string str() const {
std::ostringstream out;
out << to_string(prop) << "(";
bool first = true;
auto add = [&](std::string const& k, uint64_t v) {
if (!first) out << ", ";
first = false;
out << k << "=" << v;
};
if (p) add("p", reinterpret_cast<uint64_t>(p));
if (y != -1) add("y", static_cast<uint64_t>(y));
add("i", i);
if (s_idx) add("s", s_idx);
if (I_idx) add("I", I_idx);
if (ord_id) add("ord", ord_id);
out << ")";
return out.str();
}
// Equality (coarse; pointer identity for p is intentional)
bool operator==(property_inst const& o) const {
return prop == o.prop &&
p == o.p &&
y == o.y &&
i == o.i &&
s_idx == o.s_idx &&
I_idx == o.I_idx &&
ord_id == o.ord_id;
}
};
// Proof rule identifiers (align roughly with paper sections; can be refined later).
enum class proof_rule : unsigned {
// Skeleton rules; refine/extend as we implement specific inferences
axiom, // introduce a known/assumed property
derive, // generic derivation step (placeholder)
r_ir_ord, // rules for ir_ord propagation
r_an_del,
r_non_null,
r_ord_inv_red,
r_ord_inv_irred,
r_sgn_inv_red,
r_sgn_inv_irred,
r_connected,
r_an_sub,
r_sample,
r_repr,
r_close_holds // closes to 'holds'
};
inline const char* to_string(proof_rule r) {
switch (r) {
case proof_rule::axiom: return "axiom";
case proof_rule::derive: return "derive";
case proof_rule::r_ir_ord: return "r_ir_ord";
case proof_rule::r_an_del: return "r_an_del";
case proof_rule::r_non_null: return "r_non_null";
case proof_rule::r_ord_inv_red: return "r_ord_inv_red";
case proof_rule::r_ord_inv_irred:return "r_ord_inv_irred";
case proof_rule::r_sgn_inv_red: return "r_sgn_inv_red";
case proof_rule::r_sgn_inv_irred:return "r_sgn_inv_irred";
case proof_rule::r_connected: return "r_connected";
case proof_rule::r_an_sub: return "r_an_sub";
case proof_rule::r_sample: return "r_sample";
case proof_rule::r_repr: return "r_repr";
case proof_rule::r_close_holds: return "r_close_holds";
default: return "?";
}
}
// A single proof step: premises -> conclusion, with metadata.
struct proof_step {
proof_rule rule;
property_mapping_case ctx = property_mapping_case::case1; // for multi-case rules (e.g., 4.2)
std::vector<unsigned> premises; // indices into facts_
unsigned conclusion; // index into facts_
std::string str(std::vector<property_inst> const& facts) const {
std::ostringstream out;
out << to_string(rule) << "[case=" << static_cast<unsigned>(ctx) << "]: ";
out << "{";
for (unsigned k = 0; k < premises.size(); ++k) {
if (k) out << ", ";
out << facts[premises[k]].str();
}
out << "} => " << facts[conclusion].str();
return out.str();
}
};
// A lightweight proof object to manage facts and steps.
class levelwise_proof {
std::vector<property_inst> m_facts;
std::vector<proof_step> m_steps;
// Linear lookup to avoid hashing complexity here.
int find_fact(property_inst const& f) const {
for (unsigned i = 0; i < m_facts.size(); ++i)
if (m_facts[i] == f) return static_cast<int>(i);
return -1;
}
public:
unsigned intern_fact(property_inst const& f) {
int idx = find_fact(f);
if (idx >= 0) return static_cast<unsigned>(idx);
m_facts.push_back(f);
return static_cast<unsigned>(m_facts.size() - 1);
}
unsigned add_axiom(property_inst const& concl) {
unsigned c = intern_fact(concl);
m_steps.push_back(proof_step{proof_rule::axiom, property_mapping_case::case1, {}, c});
return c;
}
unsigned add_step(proof_rule rule,
property_mapping_case ctx,
std::vector<unsigned> const& premises,
property_inst const& conclusion) {
unsigned c = intern_fact(conclusion);
m_steps.push_back(proof_step{rule, ctx, premises, c});
return c;
}
std::string dump() const {
std::ostringstream out;
for (auto const& st : m_steps)
out << st.str(m_facts) << "\n";
return out.str();
}
std::vector<property_inst> const& facts() const { return m_facts; }
std::vector<proof_step> const& steps() const { return m_steps; }
};
// Property propagation mapping: for each property, the set of properties it implies (see levelwise paper, e.g., rule 4.2)
// Overload: property_dependencies with context (for rules like 4.2 with multiple cases).
// Note: This is a scaffold. Fill per paper’s precise rules (TODO).
inline std::vector<polynom_property>
get_property_dependencies(polynom_property prop, property_mapping_case /*p_case*/, polynomial_ref& /*p*/, unsigned /*i*/) {
std::vector<polynom_property> ret;
switch (prop) {
case polynom_property::ir_ord:
// TODO: fill using Property 4.3 / Rule 4.2 cases; currently no direct property implications recorded here.
break;
case polynom_property::an_del:
// Example: an_del(p) might imply non_null(p) or be used in combination with others; leave empty until specified.
break;
case polynom_property::non_null:
// Usually terminal for p; no generic implications without context.
break;
case polynom_property::ord_inv_reducible:
// Often accompanies sign invariance for reducible polynomials; no generic implication recorded here.
break;
case polynom_property::ord_inv_irreducible:
// Likewise for irreducible.
break;
case polynom_property::sgn_inv_reducible:
// In many presentations, sign invariance implies order invariance on reducible components.
// If the paper states so, uncomment:
// ret.push_back(polynom_property::ord_inv_reducible);
break;
case polynom_property::sgn_inv_irreducible:
// If sign invariance implies order invariance for irreducible p, uncomment:
// ret.push_back(polynom_property::ord_inv_irreducible);
break;
case polynom_property::connected:
// connected(i) might enable sample or representation derivations; leave empty here.
break;
case polynom_property::an_sub:
// an_sub(i) may enable additional sampling; leave empty here.
break;
case polynom_property::sample:
// sample(s) is often a leaf for evaluating properties at s.
break;
case polynom_property::repr:
// repr(I, s) together with others may lead to holds; no generic implication alone.
break;
case polynom_property::holds:
// Terminal goal, no further implications.
break;
default:
break;
}
return ret;
}
// Example driver/stub that will eventually orchestrate Levelwise projection with proof logging.
void lewelwise_project(polynomial_ref_vector & /*ps*/, var /*max_x*/) {
//std::cout << "call\n";
//exit(0);
// Scaffold example (no-ops for now):
// levelwise_proof pr;
// for (auto* p : ps) { pr.add_axiom(property_inst::of(p, polynom_property::an_del, /*level*/0)); }
// std::cout << pr.dump();
}
}

74
src/nlsat/levelwise.h
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@ -1,78 +1,6 @@
// Context for property propagation (e.g., which case of rule 4.2 applies)
enum class property_mapping_case : unsigned {
case1 = 0,
case2 = 1,
case3 = 3,
};
/*++
Copyright (c) 2025
Module Name:
levelwise.h
Abstract:
Levelwise algorithm property and mapping definitions (see levelwise paper).
--*/
#pragma once
#include <vector>
#include "nlsat_types.h"
namespace nlsat {
/**
* Properties for indexed roots, in the order specified by the levelwise paper.
* The order is important for the algorithm and must match the paper exactly.
*/
enum class polynom_property : unsigned {
ir_ord, // ir_ord(≼, s) for all ≼ for roots of level i and s ∈ Ri−1
an_del, // an_del(p) for all p of level i
non_null, // non_null(p) for all p of level i
ord_inv_reducible, // ord_inv(p) for all reducible p of level i
ord_inv_irreducible, // ord_inv(p) for all irreducible p of level i
sgn_inv_reducible, // sgn_inv(p) for all reducible p of level i
sgn_inv_irreducible, // sgn_inv(p) for all irreducible p of level i
connected, // connected(i)
an_sub, // an_sub(i)
sample, // sample(s) for all s ∈ Ri of level i
repr, // repr(I, s) for all I of level i and s ∈ ...
holds,
_count // always last: number of properties
};
// Utility: property to string (for debugging, logging, etc.)
inline const char* to_string(polynom_property prop) {
switch (prop) {
case polynom_property::ir_ord: return "ir_ord";
case polynom_property::an_del: return "an_del";
case polynom_property::non_null: return "non_null";
case polynom_property::ord_inv_reducible: return "ord_inv_reducible";
case polynom_property::ord_inv_irreducible: return "ord_inv_irreducible";
case polynom_property::sgn_inv_reducible: return "sgn_inv_reducible";
case polynom_property::sgn_inv_irreducible: return "sgn_inv_irreducible";
case polynom_property::connected: return "connected";
case polynom_property::an_sub: return "an_sub";
case polynom_property::sample: return "sample";
case polynom_property::repr: return "repr";
case polynom_property::holds: return "holds";
default: throw "unknown";
}
}
// Property propagation mapping: for each property, the set of properties it implies (see levelwise paper, e.g., rule 4.2)
// Example: property_dependencies[root_property::sgn_inv] = {root_property::ord_inv, ...}
// Overload: property_dependencies with context (for rules like 4.2 with multiple cases)
inline const std::vector<polynom_property> get_property_dependencies(polynom_property prop, property_mapping_case p_case) {
// Each property has a table of vectors, one per context case
static const std::vector<polynom_property> table[][10] = {
};
return table[(unsigned)prop][(unsigned)p_case];
}
void lewelwise_project(polynomial_ref_vector & ps, var max_x);
} // namespace nlsat

2
src/nlsat/nlsat_explain.cpp
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@ -1246,7 +1246,7 @@ namespace nlsat {
polynomial_ref_vector samples(m_pm);
lewelwise_project(ps, max_x);
if (x < max_x)
cac_add_cell_lits(ps, x, samples);