mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-06 17:44:08 +00:00
Code Activity

fixing simplex

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2014-02-20 08:53:36 -08:00
parent fde48d2c0e
commit ea65f32914
3 changed files with 77 additions and 38 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
src/math/simplex/simplex.h
View file

@ -98,6 +98,7 @@ namespace simplex {
random_gen m_random;
uint_set m_left_basis;
unsigned m_infeasible_var;
unsigned_vector m_base_vars;
public:
simplex():

111
src/math/simplex/simplex_def.h
View file

@ -27,46 +27,87 @@ namespace simplex {
template<typename Ext>
typename simplex<Ext>::row
simplex<Ext>::add_row(var_t base, unsigned num_vars, var_t const* vars, numeral const* coeffs) {
scoped_numeral base_coeff(m);
scoped_eps_numeral value(em), tmp(em);
simplex<Ext>::add_row(var_t base_var, unsigned num_vars, var_t const* vars, numeral const* coeffs) {
m_base_vars.reset();
row r = M.mk_row();
for (unsigned i = 0; i < num_vars; ++i) {
if (!m.is_zero(coeffs[i])) {
var_t v = vars[i];
if (is_base(v)) {
m_base_vars.push_back(i);
}
M.add_var(r, coeffs[i], v);
if (v == base) {
m.set(base_coeff, coeffs[i]);
}
else {
SASSERT(!is_base(v));
em.mul(m_vars[v].m_value, coeffs[i], tmp);
em.add(value, tmp, value);
}
}
}
#if 0
if (m.is_pos(base_coeff)) {
scoped_numeral minus_one(m);
m.set(minus_one, -1);
M.mul(r, minus_one);
m.neg(base_coeff);
em.neg(value);
scoped_numeral mul(m), a(m), b(m), c(m);
m.set(mul, 1);
for (unsigned i = 0; i < m_base_vars.size(); ++i) {
var_t v = vars[m_base_vars[i]];
m.mul(coeffs[m_base_vars[i]], mul, a);
m.set(b, m_vars[v].m_base_coeff);
m.lcm(a, b, c);
TRACE("simplex",
m.display(tout << "a: ", a);
m.display(tout << "b v" << v << " : ", b);
m.display(tout << "c: ", c);
tout << "\n";
if (m.is_zero(b)) {
display(tout);
});
SASSERT(is_base(v));
m.abs(c);
m.div(c, a, b);
m.div(c, m_vars[v].m_base_coeff, a);
m.set(mul, a);
m.abs(mul);
M.mul(r, b);
m.neg(a);
M.add(r, a, row(m_vars[v].m_base2row));
}
SASSERT(m.is_neg(base_coeff));
#endif
SASSERT(!is_base(base));
scoped_numeral base_coeff(m);
scoped_eps_numeral value(em), tmp(em);
row_iterator it = M.row_begin(r), end = M.row_end(r);
for (; it != end; ++it) {
var_t v = it->m_var;
if (v == base_var) {
m.set(base_coeff, it->m_coeff);
}
else {
SASSERT(!is_base(v));
em.mul(m_vars[v].m_value, it->m_coeff, tmp);
em.add(value, tmp, value);
}
}
SASSERT(!m.is_zero(base_coeff));
TRACE("simplex",
for (unsigned i = 0; i < num_vars; ++i) {
m.display(tout << "v" << vars[i] << " * ", coeffs[i]); tout << " ";
if (i + 1 < num_vars) tout << " + ";
}
tout << "\n";
row_iterator it2 = M.row_begin(r);
bool first = true;
for (; it2 != end; ++it2) {
if (!first) tout << " + ";
tout << "v" << it2->m_var << " * ";
m.display(tout, it2->m_coeff); tout << " ";
first = false;
}
tout << "\n";
);
SASSERT(!is_base(base_var));
em.neg(value);
em.div(value, base_coeff, value);
while (m_row2base.size() <= r.id()) {
m_row2base.push_back(null_var);
}
m_row2base[r.id()] = base;
m_vars[base].m_base2row = r.id();
m_vars[base].m_is_base = true;
m.set(m_vars[base].m_base_coeff, base_coeff);
em.set(m_vars[base].m_value, value);
add_patch(base);
m_row2base[r.id()] = base_var;
m_vars[base_var].m_base2row = r.id();
m_vars[base_var].m_is_base = true;
m.set(m_vars[base_var].m_base_coeff, base_coeff);
em.set(m_vars[base_var].m_value, value);
add_patch(base_var);
SASSERT(well_formed_row(r));
return r;
}
@ -89,6 +130,7 @@ namespace simplex {
template<typename Ext>
void simplex<Ext>::del_row(row const& r) {
TRACE("simplex", tout << r.id() << "\n";);
m_vars[m_row2base[r.id()]].m_is_base = false;
m_row2base[r.id()] = null_var;
M.del(r);
@ -174,7 +216,6 @@ namespace simplex {
template<typename Ext>
lbool simplex<Ext>::make_feasible() {
TRACE("simplex", tout << "\n";);
m_left_basis.reset();
m_infeasible_var = null_var;
unsigned num_iterations = 0;
@ -339,11 +380,13 @@ namespace simplex {
scoped_eps_numeral value(em);
bool is_below;
if (below_lower(x_i)) {
is_below = true;
SASSERT(is_base(x_i));
is_below = m.is_pos(m_vars[x_i].m_base_coeff);
value = m_vars[x_i].m_lower;
}
else if (above_upper(x_i)) {
is_below = false;
SASSERT(is_base(x_i));
is_below = m.is_neg(m_vars[x_i].m_base_coeff);
value = m_vars[x_i].m_upper;
}
else {
@ -773,12 +816,6 @@ namespace simplex {
template<typename Ext>
bool simplex<Ext>::well_formed_row(row const& r) const {
//
// TBD: extract coefficient of base variable and compare
// with m_vars[s].m_base_coeff;
//
// check that sum of assignments add up to 0 for every row.
var_t s = m_row2base[r.id()];
SASSERT(m_vars[s].m_base2row == r.id());
SASSERT(m_vars[s].m_is_base);
@ -788,7 +825,7 @@ namespace simplex {
for (; it != end; ++it) {
em.mul(m_vars[it->m_var].m_value, it->m_coeff, tmp);
sum += tmp;
SASSERT(s != it->m_var || m.eq(m_vars[e].m_base_coeff, it->m_coeff));
SASSERT(s != it->m_var || m.eq(m_vars[s].m_base_coeff, it->m_coeff));
}
SASSERT(em.is_zero(sum));

3
src/smt/theory_pb.cpp
View file

@ -360,6 +360,7 @@ namespace smt {
theory_var slack;
bool_var abv2;
row r;
TRACE("pb", display(tout << abv <<"\n", rep););
if (m_ineq_rep.find(rep, abv2)) {
slack = abv2;
r = m_ineq_row_info.find(abv2).m_row;
@ -1286,10 +1287,10 @@ namespace smt {
if (m_enable_simplex) {
row_info r_info;
VERIFY(m_ineq_row_info.find(v, r_info));
m_simplex.del_row(r_info.m_row);
m_ineq_row_info.erase(v);
bool_var v2 = m_ineq_rep.find(r_info.m_rep);
if (v == v2) {
m_simplex.del_row(r_info.m_row);
m_ineq_rep.erase(r_info.m_rep);
}
}