mirror of
https://github.com/Z3Prover/z3
synced 2025-04-23 17:15:31 +00:00
fix mb maximization logic, so far not accessible
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
parent
c7ff05cc78
commit
9c099d6b1b
12 changed files with 318 additions and 109 deletions
|
|
@ -41,7 +41,6 @@ namespace opt {
|
|||
|
||||
|
||||
bool model_based_opt::invariant() {
|
||||
// variables in each row are sorted.
|
||||
for (unsigned i = 0; i < m_rows.size(); ++i) {
|
||||
if (!invariant(i, m_rows[i])) {
|
||||
return false;
|
||||
|
|
@ -50,19 +49,21 @@ namespace opt {
|
|||
return true;
|
||||
}
|
||||
|
||||
#define PASSERT(_e_) if (!(_e_)) { TRACE("opt", display(tout, r);); SASSERT(_e_); }
|
||||
|
||||
bool model_based_opt::invariant(unsigned index, row const& r) {
|
||||
rational val = r.m_coeff;
|
||||
vector<var> const& vars = r.m_vars;
|
||||
for (unsigned i = 0; i < vars.size(); ++i) {
|
||||
var const& v = vars[i];
|
||||
SASSERT(i + 1 == vars.size() || v.m_id < vars[i+1].m_id);
|
||||
SASSERT(!v.m_coeff.is_zero());
|
||||
val += v.m_coeff * m_var2value[v.m_id];
|
||||
// variables in each row are sorted and have non-zero coefficients
|
||||
SASSERT(i + 1 == vars.size() || vars[i].m_id < vars[i+1].m_id);
|
||||
SASSERT(!vars[i].m_coeff.is_zero());
|
||||
}
|
||||
SASSERT(val == r.m_value);
|
||||
SASSERT(r.m_type != t_eq || val.is_zero());
|
||||
SASSERT(index == 0 || r.m_type != t_lt || val.is_neg());
|
||||
SASSERT(index == 0 || r.m_type != t_le || !val.is_pos());
|
||||
|
||||
PASSERT(r.m_value == get_row_value(r));
|
||||
PASSERT(r.m_type != t_eq || r.m_value.is_zero());
|
||||
// values satisfy constraints
|
||||
PASSERT(index == 0 || r.m_type != t_lt || r.m_value.is_neg());
|
||||
PASSERT(index == 0 || r.m_type != t_le || !r.m_value.is_pos());
|
||||
return true;
|
||||
}
|
||||
|
||||
|
|
@ -90,20 +91,25 @@ namespace opt {
|
|||
//
|
||||
inf_eps model_based_opt::maximize() {
|
||||
SASSERT(invariant());
|
||||
unsigned_vector other;
|
||||
unsigned_vector bound_trail, bound_vars;
|
||||
TRACE("opt", display(tout << "tableau\n"););
|
||||
while (!objective().m_vars.empty()) {
|
||||
TRACE("opt", display(tout << "tableau\n"););
|
||||
var v = objective().m_vars.back();
|
||||
unsigned x = v.m_id;
|
||||
rational const& coeff = v.m_coeff;
|
||||
unsigned bound_row_index;
|
||||
rational bound_coeff;
|
||||
other.reset();
|
||||
if (find_bound(x, bound_row_index, bound_coeff, other, coeff.is_pos())) {
|
||||
if (find_bound(x, bound_row_index, bound_coeff, coeff.is_pos())) {
|
||||
SASSERT(!bound_coeff.is_zero());
|
||||
for (unsigned i = 0; i < other.size(); ++i) {
|
||||
resolve(bound_row_index, bound_coeff, other[i], x);
|
||||
TRACE("opt", display(tout << "update: " << v << " ", objective());
|
||||
for (unsigned i = 0; i < m_above.size(); ++i) {
|
||||
display(tout << "resolve: ", m_rows[m_above[i]]);
|
||||
});
|
||||
for (unsigned i = 0; i < m_above.size(); ++i) {
|
||||
resolve(bound_row_index, bound_coeff, m_above[i], x);
|
||||
}
|
||||
for (unsigned i = 0; i < m_below.size(); ++i) {
|
||||
resolve(bound_row_index, bound_coeff, m_below[i], x);
|
||||
}
|
||||
// coeff*x + objective <= ub
|
||||
// a2*x + t2 <= 0
|
||||
|
|
@ -116,6 +122,8 @@ namespace opt {
|
|||
bound_vars.push_back(x);
|
||||
}
|
||||
else {
|
||||
TRACE("opt", display(tout << "unbound: " << v << " ", objective()););
|
||||
update_values(bound_vars, bound_trail);
|
||||
return inf_eps::infinity();
|
||||
}
|
||||
}
|
||||
|
|
@ -136,15 +144,33 @@ namespace opt {
|
|||
}
|
||||
|
||||
|
||||
void model_based_opt::update_value(unsigned x, rational const& val) {
|
||||
rational old_val = m_var2value[x];
|
||||
m_var2value[x] = val;
|
||||
unsigned_vector const& row_ids = m_var2row_ids[x];
|
||||
for (unsigned i = 0; i < row_ids.size(); ++i) {
|
||||
unsigned row_id = row_ids[i];
|
||||
rational coeff = get_coefficient(row_id, x);
|
||||
if (coeff.is_zero()) {
|
||||
continue;
|
||||
}
|
||||
row & r = m_rows[row_id];
|
||||
rational delta = coeff * (val - old_val);
|
||||
r.m_value += delta;
|
||||
SASSERT(invariant(row_id, r));
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
void model_based_opt::update_values(unsigned_vector const& bound_vars, unsigned_vector const& bound_trail) {
|
||||
rational eps(0);
|
||||
for (unsigned i = bound_trail.size(); i > 0; ) {
|
||||
--i;
|
||||
unsigned x = bound_vars[i];
|
||||
row& r = m_rows[bound_trail[i]];
|
||||
rational val = r.m_coeff;
|
||||
rational x_val;
|
||||
rational x_coeff;
|
||||
rational old_x_val = m_var2value[x];
|
||||
rational new_x_val;
|
||||
rational x_coeff, eps(0);
|
||||
vector<var> const& vars = r.m_vars;
|
||||
for (unsigned j = 0; j < vars.size(); ++j) {
|
||||
var const& v = vars[j];
|
||||
|
|
@ -155,28 +181,21 @@ namespace opt {
|
|||
val += m_var2value[v.m_id]*v.m_coeff;
|
||||
}
|
||||
}
|
||||
TRACE("opt", display(tout << "v" << x << " val: " << val
|
||||
<< " coeff_x: " << x_coeff << " val_x: " << m_var2value[x] << " ", r); );
|
||||
SASSERT(!x_coeff.is_zero());
|
||||
x_val = -val/x_coeff;
|
||||
//
|
||||
//
|
||||
// ax + t < 0
|
||||
// <=> x < -t/a
|
||||
// <=> x := -t/a - epsilon
|
||||
//
|
||||
if (r.m_type == t_lt) {
|
||||
// Adjust epsilon to be
|
||||
if (!x_val.is_zero() && (eps.is_zero() || eps >= abs(x_val))) {
|
||||
eps = abs(x_val)/rational(2);
|
||||
}
|
||||
if (!r.m_value.is_zero() && (eps.is_zero() || eps >= abs(r.m_value))) {
|
||||
eps = abs(r.m_value)/rational(2);
|
||||
}
|
||||
new_x_val = -val/x_coeff;
|
||||
|
||||
if (r.m_type == t_lt) {
|
||||
eps = abs(old_x_val - new_x_val)/rational(2);
|
||||
eps = std::min(rational::one(), eps);
|
||||
SASSERT(!eps.is_zero());
|
||||
|
||||
//
|
||||
// ax + t < 0
|
||||
// <=> x < -t/a
|
||||
// <=> x := -t/a - epsilon
|
||||
//
|
||||
if (x_coeff.is_pos()) {
|
||||
x_val -= eps;
|
||||
new_x_val -= eps;
|
||||
}
|
||||
//
|
||||
// -ax + t < 0
|
||||
|
|
@ -185,27 +204,47 @@ namespace opt {
|
|||
// <=> x > t/a
|
||||
// <=> x := t/a + epsilon
|
||||
//
|
||||
else if (x_coeff.is_neg()) {
|
||||
x_val += eps;
|
||||
else {
|
||||
new_x_val += eps;
|
||||
}
|
||||
}
|
||||
m_var2value[x] = x_val;
|
||||
r.m_value = (x_val * x_coeff) + val;
|
||||
TRACE("opt", display(tout << "v" << x
|
||||
<< " coeff_x: " << x_coeff
|
||||
<< " old_x_val: " << old_x_val
|
||||
<< " new_x_val: " << new_x_val
|
||||
<< " eps: " << eps << " ", r); );
|
||||
m_var2value[x] = new_x_val;
|
||||
|
||||
TRACE("opt", display(tout << "v" << x << " val: " << val << " coeff_x: "
|
||||
<< x_coeff << " val_x: " << m_var2value[x] << " ", r); );
|
||||
r.m_value = get_row_value(r);
|
||||
SASSERT(invariant(bound_trail[i], r));
|
||||
}
|
||||
|
||||
// update and check bounds for all other affected rows.
|
||||
for (unsigned i = bound_trail.size(); i > 0; ) {
|
||||
--i;
|
||||
unsigned x = bound_vars[i];
|
||||
unsigned_vector const& row_ids = m_var2row_ids[x];
|
||||
for (unsigned j = 0; j < row_ids.size(); ++j) {
|
||||
unsigned row_id = row_ids[j];
|
||||
row & r = m_rows[row_id];
|
||||
r.m_value = get_row_value(r);
|
||||
SASSERT(invariant(row_id, r));
|
||||
}
|
||||
}
|
||||
SASSERT(invariant());
|
||||
}
|
||||
|
||||
bool model_based_opt::find_bound(unsigned x, unsigned& bound_row_index, rational& bound_coeff, unsigned_vector& other, bool is_pos) {
|
||||
bool model_based_opt::find_bound(unsigned x, unsigned& bound_row_index, rational& bound_coeff, bool is_pos) {
|
||||
bound_row_index = UINT_MAX;
|
||||
rational lub_val;
|
||||
rational const& x_val = m_var2value[x];
|
||||
unsigned_vector const& row_ids = m_var2row_ids[x];
|
||||
uint_set visited;
|
||||
m_above.reset();
|
||||
m_below.reset();
|
||||
for (unsigned i = 0; i < row_ids.size(); ++i) {
|
||||
unsigned row_id = row_ids[i];
|
||||
SASSERT(row_id != m_objective_id);
|
||||
if (visited.contains(row_id)) {
|
||||
continue;
|
||||
}
|
||||
|
|
@ -226,24 +265,34 @@ namespace opt {
|
|||
else if ((value == lub_val && r.m_type == opt::t_lt) ||
|
||||
(is_pos && value < lub_val) ||
|
||||
(!is_pos && value > lub_val)) {
|
||||
other.push_back(bound_row_index);
|
||||
m_above.push_back(bound_row_index);
|
||||
lub_val = value;
|
||||
bound_row_index = row_id;
|
||||
bound_row_index = row_id;
|
||||
bound_coeff = a;
|
||||
}
|
||||
else {
|
||||
other.push_back(row_id);
|
||||
m_above.push_back(row_id);
|
||||
}
|
||||
}
|
||||
else {
|
||||
r.m_alive = false;
|
||||
m_below.push_back(row_id);
|
||||
}
|
||||
}
|
||||
}
|
||||
return bound_row_index != UINT_MAX;
|
||||
}
|
||||
|
||||
rational model_based_opt::get_coefficient(unsigned row_id, unsigned var_id) {
|
||||
|
||||
rational model_based_opt::get_row_value(row const& r) const {
|
||||
vector<var> const& vars = r.m_vars;
|
||||
rational val = r.m_coeff;
|
||||
for (unsigned i = 0; i < vars.size(); ++i) {
|
||||
var const& v = vars[i];
|
||||
val += v.m_coeff * m_var2value[v.m_id];
|
||||
}
|
||||
return val;
|
||||
}
|
||||
|
||||
rational model_based_opt::get_coefficient(unsigned row_id, unsigned var_id) const {
|
||||
row const& r = m_rows[row_id];
|
||||
if (r.m_vars.empty()) {
|
||||
return rational::zero();
|
||||
|
|
|
|||
|
|
@ -65,24 +65,29 @@ namespace opt {
|
|||
vector<rational> m_var2value;
|
||||
vector<var> m_new_vars;
|
||||
unsigned_vector m_lub, m_glb;
|
||||
unsigned_vector m_above, m_below;
|
||||
|
||||
bool invariant();
|
||||
bool invariant(unsigned index, row const& r);
|
||||
|
||||
row& objective() { return m_rows[0]; }
|
||||
|
||||
bool find_bound(unsigned x, unsigned& bound_index, rational& bound_coeff, unsigned_vector& other, bool is_pos);
|
||||
bool find_bound(unsigned x, unsigned& bound_index, rational& bound_coeff, bool is_pos);
|
||||
|
||||
rational get_coefficient(unsigned row_id, unsigned var_id);
|
||||
rational get_coefficient(unsigned row_id, unsigned var_id) const;
|
||||
|
||||
rational get_row_value(row const& r) const;
|
||||
|
||||
void resolve(unsigned row_src, rational const& a1, unsigned row_dst, unsigned x);
|
||||
|
||||
void mul_add(bool same_sign, unsigned row_id1, rational const& c, unsigned row_id2);
|
||||
|
||||
void set_row(unsigned row_id, vector<var> const& coeffs, rational const& c, ineq_type rel);
|
||||
|
||||
void set_row(unsigned row_id, vector<var> const& coeffs, rational const& c, ineq_type rel);
|
||||
|
||||
void update_values(unsigned_vector const& bound_vars, unsigned_vector const& bound_trail);
|
||||
|
||||
void update_value(unsigned x, rational const& val);
|
||||
|
||||
void project(unsigned var);
|
||||
|
||||
void solve_for(unsigned row_id, unsigned x);
|
||||
|
|
@ -132,5 +137,6 @@ namespace opt {
|
|||
|
||||
std::ostream& operator<<(std::ostream& out, opt::ineq_type ie);
|
||||
|
||||
inline std::ostream& operator<<(std::ostream& out, opt::model_based_opt::var const v) { return out << "v" << v.m_id; }
|
||||
|
||||
#endif
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue