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some simplifications in cheap eqs

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2020-06-08 21:16:23 -07:00
parent 4de38d09e2
commit dd30b5e3af
5 changed files with 40 additions and 22 deletions
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12
src/math/lp/bound_analyzer_on_row.h
View file

@ -330,11 +330,19 @@ private:
}
void analyze_eq() {
if (m_bp.lp().settings().cheap_eqs()) {
switch (m_bp.lp().settings().cheap_eqs()) {
case 0:
return;
case 1:
m_bp.try_create_eq(m_row_index);
break;
case 2:
m_bp.try_create_eq_table(m_row_index);
break;
default:
UNREACHABLE();
}
}
};
}

29
src/math/lp/lp_bound_propagator.h
View file

@ -9,6 +9,11 @@
namespace lp {
template <typename T>
class lp_bound_propagator {
typedef std::pair<int, impq> var_offset;
typedef pair_hash<int_hash, obj_hash<impq> > var_offset_hash;
typedef map<var_offset, unsigned, var_offset_hash, default_eq<var_offset> > var_offset2row_id;
var_offset2row_id m_var_offset2row_id;
struct impq_eq { bool operator()(const impq& a, const impq& b) const {return a == b;}};
// vertex represents a pair (row,x) or (row,y) for an offset row.
@ -62,14 +67,6 @@ class lp_bound_propagator {
std::unordered_map<unsigned, unsigned> m_improved_upper_bounds;
T& m_imp;
impq m_zero;
typedef std::pair<unsigned, unsigned> upair;
struct uphash {
unsigned operator()(const upair& p) const { return combine_hash(p.first, p.second); }
};
struct upeq {
unsigned operator()(const upair& p, const upair& q) const { return p == q; }
};
hashtable<upair, uphash, upeq> m_reported_pairs; // contain the pairs of columns (first < second)
public:
vector<implied_bound> m_ibounds;
lp_bound_propagator(T& imp): m_imp(imp), m_zero(impq(0)) {}
@ -156,7 +153,7 @@ public:
offset += c.coeff() * lp().get_lower_bound(c.var());
}
if (offset.is_zero() &&
!pair_is_reported(row[x_index].var(), row[y_index].var())) {
!pair_is_reported_or_congruent(row[x_index].var(), row[y_index].var())) {
lp::explanation ex;
explain_fixed_in_row(row_index, ex);
add_eq_on_columns(ex, row[x_index].var(), row[y_index].var());
@ -164,17 +161,16 @@ public:
return true;
}
bool pair_is_reported(lpvar j, lpvar k) const {
return j < k? m_reported_pairs.contains(std::make_pair(j, k)) :
m_reported_pairs.contains(std::make_pair(k, j));
bool pair_is_reported_or_congruent(lpvar j, lpvar k) const {
return m_imp.congruent_or_irrelevant(lp().column_to_reported_index(j), lp().column_to_reported_index(k));
}
void check_for_eq_and_add_to_offset_table(vertex* v) {
vertex *k; // the other vertex index
vertex *k; // the other vertex
if (m_offset_to_verts.find(v->offset(), k)) {
if (column(k) != column(v) &&
!pair_is_reported(column(k),column(v)))
!pair_is_reported_or_congruent(column(k),column(v)))
report_eq(k, v);
} else {
TRACE("cheap_eq", tout << "registered offset " << v->offset() << " to " << v << "\n";);
@ -211,8 +207,6 @@ public:
void add_eq_on_columns(const explanation& exp, lpvar v_i_col, lpvar v_j_col) {
SASSERT(v_i_col != v_j_col);
upair p = v_i_col < v_j_col? upair(v_i_col, v_j_col) :upair(v_j_col, v_i_col);
m_reported_pairs.insert(p);
unsigned i_e = lp().column_to_reported_index(v_i_col);
unsigned j_e = lp().column_to_reported_index(v_j_col);
TRACE("cheap_eq", tout << "reporting eq " << i_e << ", " << j_e << "\n";
@ -222,6 +216,9 @@ public:
m_imp.add_eq(i_e, j_e, exp);
}
void try_create_eq_table(unsigned row_index) {
}
explanation get_explanation_from_path(const ptr_vector<vertex>& path) const {
explanation ex;

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

@ -205,12 +205,12 @@ public:
private:
bool m_enable_hnf;
bool m_print_external_var_name;
bool m_cheap_eqs;
unsigned m_cheap_eqs;
public:
bool print_external_var_name() const { return m_print_external_var_name; }
bool& print_external_var_name() { return m_print_external_var_name; }
bool cheap_eqs() const { return m_cheap_eqs;}
bool& cheap_eqs() { return m_cheap_eqs;}
unsigned cheap_eqs() const { return m_cheap_eqs;}
unsigned& cheap_eqs() { return m_cheap_eqs;}
unsigned hnf_cut_period() const { return m_hnf_cut_period; }
void set_hnf_cut_period(unsigned period) { m_hnf_cut_period = period; }
unsigned random_next() { return m_rand(); }

2
src/smt/params/smt_params_helper.pyg
View file

@ -41,7 +41,7 @@ def_module_params(module_name='smt',
('bv.reflect', BOOL, True, 'create enode for every bit-vector term'),
('bv.enable_int2bv', BOOL, True, 'enable support for int2bv and bv2int operators'),
('arith.random_initial_value', BOOL, False, 'use random initial values in the simplex-based procedure for linear arithmetic'),
('arith.cheap_eqs', BOOL, True, 'true for extracting cheap equalities'),
('arith.cheap_eqs', UINT, 0, '0 - do not run, 1 - use tree, 2 - use table'),
('arith.solver', UINT, 6, 'arithmetic solver: 0 - no solver, 1 - bellman-ford based solver (diff. logic only), 2 - simplex based solver, 3 - floyd-warshall based solver (diff. logic only) and no theory combination 4 - utvpi, 5 - infinitary lra, 6 - lra solver'),
('arith.nl', BOOL, True, '(incomplete) nonlinear arithmetic support based on Groebner basis and interval propagation, relevant only if smt.arith.solver=2'),
('arith.nl.gb', BOOL, True, 'groebner Basis computation, this option is ignored when arith.nl=false, relevant only if smt.arith.solver=2'),

13
src/smt/theory_lra.cpp
View file

@ -1592,6 +1592,19 @@ public:
void reset_variable_values() {
m_variable_values.clear();
}
bool congruent_or_irrelevant(lpvar k, lpvar j) {
theory_var kv = lp().local_to_external(k);
if (kv == null_theory_var)
return true;
theory_var jv = lp().local_to_external(j);
if (jv == null_theory_var)
return true;
enode * n0 = get_enode(kv);
enode * n1 = get_enode(jv);
return n0->get_root() == n1->get_root();
}
void random_update() {
if (m_nla)