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fixes in tigthening

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2024-11-03 16:01:12 -08:00 committed by Lev Nachmanson
parent 9164672d42
commit 3fcc5a2227
1 changed files with 64 additions and 51 deletions
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115
src/math/lp/dioph_eq.cpp
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@ -4,6 +4,7 @@
#include "math/lp/lp_utils.h"
#include <list>
#include <queue>
unsigned glb=0;
namespace lp {
// This class represents a term with an added constant number c, in form sum {x_i*a_i} + c.
class dioph_eq::imp {
@ -85,7 +86,7 @@ namespace lp {
std::ostream& print_S(std::ostream & out) {
out << "S:\n";
for (unsigned i : m_s) {
print_eprime_entry(i, out);
print_entry(i, out);
}
return out;
}
@ -156,14 +157,14 @@ namespace lp {
S,
NO_S_NO_F
};
struct eprime_entry {
struct entry {
unsigned m_row_index; // the index of the row in the constraint matrix that m_e corresponds to
// originally m_l is the column defining the term m_e was constructed from
lar_term m_l;
mpq m_c; // the constant of the term
entry_status m_entry_status;
};
std_vector<eprime_entry> m_eprime;
std_vector<entry> m_eprime;
// the terms are stored in m_A and m_c
static_matrix<mpq, mpq> m_e_matrix; // the rows of the matrix are the terms, without the constant part
int_solver& lia;
@ -183,11 +184,11 @@ namespace lp {
// suppose e.m_l = sum {coeff*k}, then subst(e.m_e) = fix_var(sum {coeff*lar.get_term(k)})
std_vector<unsigned> m_k2s;
std_vector<unsigned> m_fresh_definitions; // seems only needed in the debug version in remove_fresh_vars
unsigned m_conflict_index = -1; // m_eprime[m_conflict_index] gives the conflict
public:
imp(int_solver& lia, lar_solver& lra): lia(lia), lra(lra) {}
term_o get_term_from_e_matrix(unsigned i) const {
term_o get_term_from_entry(unsigned i) const {
term_o t;
for (const auto & p: m_e_matrix.m_rows[i]) {
t.add_monomial(p.coeff(), p.var());
@ -197,13 +198,13 @@ namespace lp {
}
// the term has form sum(a_i*x_i) - t.j() = 0,
// i is the index of the term in the lra.m_terms
void fill_eprime_entry(const lar_term& t) {
void fill_entry(const lar_term& t) {
TRACE("dioph_eq", print_lar_term_L(t, tout) << std::endl;);
unsigned i = static_cast<unsigned>(m_eprime.size());
eprime_entry te = {i, lar_term(t.j()), mpq(0), entry_status::NO_S_NO_F};
entry te = {i, lar_term(t.j()), mpq(0), entry_status::NO_S_NO_F};
m_f.push_back(te.m_row_index);
m_eprime.push_back(te);
eprime_entry& e = m_eprime.back();
entry& e = m_eprime.back();
m_e_matrix.add_row();
SASSERT(m_e_matrix.row_count() == m_eprime.size()); // this invariant is going to be broken
@ -226,7 +227,7 @@ namespace lp {
m_e_matrix.add_new_element(e.m_row_index, j, - mpq(1));
}
e.m_entry_status = entry_status::F;
TRACE("dioph_eq", print_eprime_entry(e, tout););
TRACE("dioph_eq", print_entry(e, tout););
SASSERT(entry_invariant(e));
}
@ -256,7 +257,7 @@ namespace lp {
TRACE("dioph_eq", tout << "not all vars are int and small\n";);
continue;
}
fill_eprime_entry(t);
fill_entry(t);
}
}
@ -301,7 +302,7 @@ namespace lp {
return false;
}
void prepare_lia_branch_report(const eprime_entry & e, const mpq& g, const mpq new_c) {
void prepare_lia_branch_report(const entry & e, const mpq& g, const mpq new_c) {
/* We have ep.m_e/g = 0, or sum((coff_i/g)*x_i) + new_c = 0,
or sum((coeff_i/g)*x_i) = -new_c, where new_c is not an integer
Then sum((coeff_i/g)*x_i) <= floor(-new_c) or sum((coeff_i/g)*x_i) >= ceil(-new_c)
@ -321,8 +322,8 @@ namespace lp {
// it is needed by the next steps
// the conflict can be used to report "cuts from proofs"
bool normalize_e_by_gcd(unsigned row_index) {
eprime_entry& e = m_eprime[row_index];
TRACE("dioph_eq", print_eprime_entry(e, tout) << std::endl;);
entry& e = m_eprime[row_index];
TRACE("dioph_eq", print_entry(e, tout) << std::endl;);
mpq g = gcd_of_coeffs(m_e_matrix.m_rows[row_index]);
if (g.is_zero() || g.is_one()) {
SASSERT(g.is_one() || e.m_c.is_zero());
@ -336,7 +337,7 @@ namespace lp {
}
m_eprime[row_index].m_c = c_g;
e.m_l *= (1/g);
TRACE("dioph_eq", tout << "ep_m_e:"; print_eprime_entry(e, tout) << std::endl;);
TRACE("dioph_eq", tout << "ep_m_e:"; print_entry(e, tout) << std::endl;);
SASSERT(entry_invariant(e));
return true;
}
@ -373,9 +374,9 @@ namespace lp {
void subs_front_in_indexed_vector(std::queue<unsigned> & q) {
unsigned k = pop_front(q);
if (m_indexed_work_vector[k].is_zero()) return;
const eprime_entry& e = entry_for_subs(k);
const entry& e = entry_for_subs(k);
TRACE("dioph_eq", tout << "k:" << k << ", in "; print_term_o(create_term_from_ind_c(), tout) << std::endl;
tout << "subs with e:"; print_eprime_entry(e, tout) << std::endl;);
tout << "subs with e:"; print_entry(e, tout) << std::endl;);
mpq coeff = m_indexed_work_vector[k]; // need to copy since it will be zeroed
m_indexed_work_vector.erase(k); // m_indexed_work_vector[k] = 0;
@ -427,7 +428,7 @@ namespace lp {
}
return ret;
}
const eprime_entry& entry_for_subs(unsigned k) const {
const entry& entry_for_subs(unsigned k) const {
return m_eprime[m_k2s[k]];
}
@ -601,7 +602,7 @@ namespace lp {
tout << "new " << (upper? "upper":"lower" ) << " bound:" << bound << std::endl;
);
SASSERT(upper && bound < lra.get_upper_bound(j).x || !upper && bound > lra.get_lower_bound(j).x);
SASSERT((upper && bound < lra.get_upper_bound(j).x) || (!upper && bound > lra.get_lower_bound(j).x));
lconstraint_kind kind = upper? lconstraint_kind::LE: lconstraint_kind::GE;
u_dependency* dep = prev_dep;
dep = lra.mk_join(dep, explain_fixed_in_meta_term(m_tmp_l));
@ -668,8 +669,6 @@ public:
lia_move ret = tighten_with_S();
if (ret == lia_move::conflict) {
lra.settings().stats().m_dio_conflicts++;
enable_trace("arith");
enable_trace("dioph_eq");
return lia_move::conflict;
}
return lia_move::undef;
@ -718,13 +717,12 @@ public:
}
std::ostream& print_e_row(unsigned i, std::ostream& out) {
return print_term_o(get_term_from_e_matrix(i), out);
return print_term_o(get_term_from_entry(i), out);
}
// j is the variable to eliminate, it appears in row e.m_e_matrix with
// a coefficient equal to +-1
void eliminate_var_in_f(eprime_entry& e, unsigned j, int j_sign) {
TRACE("dioph_eq", tout << "eliminate var:" << j << " by using:"; print_eprime_entry(e.m_row_index, tout) << std::endl;);
SASSERT(entry_invariant(e));
void eliminate_var_in_f(entry& e, unsigned j, int j_sign) {
TRACE("dioph_eq", tout << "eliminate var:" << j << " by using:"; print_entry(e.m_row_index, tout) << std::endl;);
unsigned piv_row_index = e.m_row_index;
auto &column = m_e_matrix.m_columns[j];
int pivot_col_cell_index = -1;
@ -756,16 +754,16 @@ public:
SASSERT(c.var() != piv_row_index && entry_invariant(m_eprime[c.var()]));
mpq coeff = m_e_matrix.get_val(c);
unsigned i = c.var();
TRACE("dioph_eq", tout << "before pivot entry :"; print_eprime_entry(i, tout) << std::endl;);
TRACE("dioph_eq", tout << "before pivot entry :"; print_entry(i, tout) << std::endl;);
m_eprime[i].m_c -= j_sign * coeff*e.m_c;
m_e_matrix.pivot_row_to_row_given_cell_with_sign(piv_row_index, c, j, j_sign);
m_eprime[i].m_l -= j_sign * coeff * e.m_l;
TRACE("dioph_eq", tout << "after pivoting c_row:"; print_eprime_entry(i, tout););
TRACE("dioph_eq", tout << "after pivoting c_row:"; print_entry(i, tout););
CTRACE("dioph_eq", !entry_invariant(m_eprime[i]),
tout << "invariant delta:";
{
const auto& e = m_eprime[i];
print_term_o(get_term_from_e_matrix(e.m_row_index) - fix_vars(open_ml(e.m_l)), tout) << std::endl;
print_term_o(get_term_from_entry(e.m_row_index) - fix_vars(open_ml(e.m_l)), tout) << std::endl;
}
);
SASSERT(entry_invariant(m_eprime[i]));
@ -773,8 +771,18 @@ public:
}
}
bool entry_invariant(const eprime_entry& e) const {
return remove_fresh_vars(get_term_from_e_matrix(e.m_row_index)) == fix_vars(open_ml(e.m_l));
bool entry_invariant(const entry& e) const {
bool ret = remove_fresh_vars(get_term_from_entry(e.m_row_index)) == fix_vars(open_ml(e.m_l));
if (ret) return true;
TRACE("dioph_eq",
tout << "get_term_from_entry("<<e.m_row_index<<"):";
print_term_o(get_term_from_entry(e.m_row_index), tout) <<std::endl;
tout << "remove_fresh_vars:"; print_term_o(remove_fresh_vars(get_term_from_entry(e.m_row_index)), tout) << std::endl;
tout << "e.m_l:"; print_lar_term_L(e.m_l, tout) << std::endl;
tout << "open_ml(e.m_l):"; print_term_o(open_ml(e.m_l), tout) << std::endl;
tout << "fix_vars(open_ml(e.m_l)):"; print_term_o(fix_vars(open_ml(e.m_l)), tout) << std::endl;
);
return false;
}
term_o remove_fresh_vars(const term_o& tt) const{
@ -787,15 +795,15 @@ public:
}
while (!q.empty()) {
unsigned xt = pop_front(q);
const auto & xt_row = m_e_matrix.m_rows[m_k2s[xt]];
term_o xt_term;
for (const auto & p: xt_row) {
if (p.var() == xt) continue;
xt_term.add_monomial(p.coeff(), p.var());
}
term_o fresh_t = get_term_from_entry(m_fresh_definitions[xt]);
if (fresh_t.get_coeff(xt).is_minus_one() == false)
std::cout << "coeff:" << fresh_t.get_coeff(xt) << std::endl;
SASSERT(fresh_t.get_coeff(xt).is_minus_one());
fresh_t.erase_var(xt);
if (!t.contains(xt)) continue;
mpq xt_coeff = t.get_coeff(xt);
t.erase_var(xt);
t += xt_coeff * xt_term;
t += xt_coeff * fresh_t;
for (const auto & p: t) {
if (is_fresh_var(p.j())) {
q.push(p.j());
@ -833,6 +841,7 @@ public:
// k is the variable to substitute
void fresh_var_step(unsigned h, unsigned k, const mpq& ahk) {
SASSERT(entry_invariant(m_eprime[h]));
move_row_to_work_vector(h); // it clears the row, and puts the term in the work vector
// step 7 from the paper
// xt is the fresh variable
@ -853,7 +862,7 @@ public:
e.m_c = r;
m_e_matrix.add_new_element(h, xt, ahk);
m_eprime.push_back({fresh_row, lar_term(), mpq(0), entry_status::NO_S_NO_F});
m_eprime.push_back({fresh_row, lar_term(), q, entry_status::NO_S_NO_F});
m_e_matrix.add_new_element(fresh_row, xt, -mpq(1));
m_e_matrix.add_new_element(fresh_row, k, mpq(1));
for (unsigned i: m_indexed_work_vector.m_index) {
@ -867,22 +876,24 @@ public:
}
m_k2s.resize(std::max(k + 1, xt + 1), -1);
m_k2s[k] = m_k2s[xt] = fresh_row;
TRACE("dioph_eq", tout << "changed entry:"; print_eprime_entry(h, tout)<< std::endl;
tout << "added entry for fresh var:\n"; print_eprime_entry(fresh_row, tout) << std::endl;);
m_k2s[k] = fresh_row;
m_fresh_definitions.resize(xt + 1, -1);
m_fresh_definitions[xt] = fresh_row;
TRACE("dioph_eq", tout << "changed entry:"; print_entry(h, tout)<< std::endl;
tout << "added entry for fresh var:\n"; print_entry(fresh_row, tout) << std::endl;);
SASSERT(entry_invariant(m_eprime[h]));
SASSERT(entry_invariant(m_eprime[fresh_row]));
eliminate_var_in_f(m_eprime.back(), k, 1);
}
std::ostream& print_eprime_entry(unsigned i, std::ostream& out, bool print_dep = true) {
std::ostream& print_entry(unsigned i, std::ostream& out, bool print_dep = true) {
out << "m_eprime[" << i << "]:";
return print_eprime_entry(m_eprime[i], out, print_dep);
return print_entry(m_eprime[i], out, print_dep);
}
std::ostream& print_eprime_entry(const eprime_entry& e, std::ostream& out, bool need_print_dep = true) {
std::ostream& print_entry(const entry& e, std::ostream& out, bool need_print_dep = true) {
out << "{\n";
print_term_o(get_term_from_e_matrix(e.m_row_index), out << "\tm_e:") << ",\n";
print_term_o(get_term_from_entry(e.m_row_index), out << "\tm_e:") << ",\n";
//out << "\tstatus:" << (int)e.m_entry_status;
if (need_print_dep) {
out << "\tm_l:{"; print_lar_term_L(e.m_l, out) << "}, ";
@ -936,14 +947,16 @@ public:
break;
}
if (h == UINT_MAX) return;
auto& eprime_entry = m_eprime[h];
TRACE("dioph_eq", print_eprime_entry(h, tout););
auto [ahk, k, k_sign] = find_minimal_abs_coeff(eprime_entry.m_row_index);
TRACE("dioph_eq", tout << "ahk:" << ahk << ", k:" << k << ", k_sign:" << k_sign << std::endl;);
auto& entry = m_eprime[h];
auto [ahk, k, k_sign] = find_minimal_abs_coeff(entry.m_row_index);
TRACE("dioph_eq",
tout << "eh:"; print_entry(h, tout);
tout << "ahk:" << ahk << ", k:" << k << ", k_sign:" << k_sign << std::endl;);
if (ahk.is_one()) {
TRACE("dioph_eq", tout << "push to S:\n"; print_eprime_entry(h, tout););
TRACE("dioph_eq", tout << "push to S:\n"; print_entry(h, tout););
move_entry_from_f_to_s(k, h);
eliminate_var_in_f(eprime_entry, k , k_sign);
eliminate_var_in_f(entry, k , k_sign);
} else {
fresh_var_step(h, k, ahk*mpq(k_sign));
}
@ -959,7 +972,7 @@ public:
return;
}
SASSERT(ex.empty());
TRACE("dioph_eq", tout << "conflict:"; print_eprime_entry(m_conflict_index, tout, true) << std::endl;);
TRACE("dioph_eq", tout << "conflict:"; print_entry(m_conflict_index, tout, true) << std::endl;);
auto & ep = m_eprime[m_conflict_index];
for (auto ci: lra.flatten(explain_fixed_in_meta_term(ep.m_l))) {
ex.push_back(ci);