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add model correction

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-04-29 19:08:10 -07:00
parent c75fd02c95
commit 2428bf18f1
11 changed files with 156 additions and 65 deletions
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77
src/math/simplex/model_based_opt.cpp
View file

@ -97,9 +97,10 @@ namespace opt {
// e.g. t2/a2 >= t3/a3
// then replace a3*x + t3 by t3/a3 - t2/a2 <= 0
//
bound_type model_based_opt::maximize(rational& value) {
inf_eps model_based_opt::maximize() {
SASSERT(invariant());
unsigned_vector other;
unsigned_vector bound_trail, bound_vars;
while (!objective().m_vars.empty()) {
TRACE("opt", tout << "tableau\n";);
var v = objective().m_vars.back();
@ -120,17 +121,79 @@ namespace opt {
mul_add(m_objective_id, - coeff/bound_coeff, bound_row_index);
m_rows[bound_row_index].m_alive = false;
bound_trail.push_back(bound_row_index);
bound_vars.push_back(x);
}
else {
return unbounded;
return inf_eps::infinity();
}
}
value = objective().m_value;
//
// update the evaluation of variables to satisfy the bound.
update_values(bound_vars, bound_trail);
rational value = objective().m_value;
if (objective().m_type == t_lt) {
return strict;
return inf_eps(inf_rational(value, rational(-1)));
}
else {
return non_strict;
return inf_eps(inf_rational(value));
}
}
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 const& r = m_rows[bound_trail[i]];
rational val = r.m_coeff;
rational x_coeff;
vector<var> const& vars = r.m_vars;
for (unsigned j = 0; j < vars.size(); ++j) {
var const& v = vars[j];
if (x = v.m_id) {
x_coeff = v.m_coeff;
}
else {
val += m_var2value[v.m_id]*v.m_coeff;
}
}
SASSERT(!x_coeff.is_zero());
val /= -x_coeff;
// Adjust epsilon to be s
if (eps.is_zero() || (!val.is_zero() && eps > abs(val))) {
eps = abs(val)/rational(2);
}
if (eps.is_zero() || (!r.m_value.is_zero() && eps > abs(r.m_value))) {
eps = abs(r.m_value)/rational(2);
}
//
//
// ax + t < 0
// <=> x < -t/a
// <=> x := -t/a - epsilon
//
if (x_coeff.is_pos() && r.m_type == t_lt) {
val -= eps;
}
//
// -ax + t < 0
// <=> -ax < -t
// <=> -x < -t/a
// <=> x > t/a
// <=> x := t/a + epsilon
//
if (x_coeff.is_pos() && r.m_type == t_lt) {
val -= eps;
}
else if (x_coeff.is_neg() && r.m_type == t_lt) {
val += eps;
}
m_var2value[x] = val;
}
}
@ -343,6 +406,10 @@ namespace opt {
return v;
}
rational model_based_opt::get_value(unsigned var) {
return m_var2value[var];
}
void model_based_opt::set_row(unsigned row_id, vector<var> const& coeffs, rational const& c, ineq_type rel) {
row& r = m_rows[row_id];
rational val(c);

14
src/math/simplex/model_based_opt.h
View file

@ -23,6 +23,7 @@ Revision History:
#include "util.h"
#include "rational.h"
#include"inf_eps_rational.h"
namespace opt {
@ -38,7 +39,7 @@ namespace opt {
non_strict
};
typedef inf_eps_rational<inf_rational> inf_eps;
class model_based_opt {
public:
@ -73,7 +74,6 @@ namespace opt {
row& objective() { return m_rows[0]; }
bool find_bound(unsigned x, unsigned& bound_index, rational& bound_coeff, unsigned_vector& other, bool is_pos);
rational get_coefficient(unsigned row_id, unsigned var_id);
@ -84,6 +84,8 @@ namespace opt {
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);
public:
model_based_opt();
@ -91,6 +93,9 @@ namespace opt {
// add a fresh variable with value 'value'.
unsigned add_var(rational const& value);
// retrieve updated value of variable.
rational get_value(unsigned var_id);
// add a constraint. We assume that the constraint is
// satisfied under the values provided to the variables.
void add_constraint(vector<var> const& coeffs, rational const& c, ineq_type r);
@ -98,12 +103,13 @@ namespace opt {
// Set the objective function (linear).
void set_objective(vector<var> const& coeffs, rational const& c);
//
// find a maximal value for the objective function over the current values.
// in other words, the returned maximal value may not be globally optimal,
// but the current evaluation of variables are used to select a local
// optimal.
bound_type maximize(rational& value);
//
inf_eps maximize();
void display(std::ostream& out) const;
void display(std::ostream& out, row const& r) const;

31
src/opt/opt_context.cpp
View file

@ -1459,23 +1459,20 @@ namespace opt {
lbool context::run_qsat_opt() {
SASSERT(is_qsat_opt());
app_ref objective(m);
opt::bound_type bound;
expr_ref value(m);
lbool result = qe::maximize(m_hard_constraints, objective, value, bound, m_params);
objective const& obj = m_objectives[0];
app_ref term(obj.m_term);
if (obj.m_type == O_MINIMIZE) {
term = m_arith.mk_uminus(term);
}
inf_eps value;
lbool result = qe::maximize(m_hard_constraints, term, value, m_params);
if (result != l_undef && obj.m_type == O_MINIMIZE) {
value.neg();
}
if (result != l_undef) {
switch (bound) {
case opt::unbounded:
case opt::strict:
case opt::non_strict:
// set_max
break;
// TBD:
default:
break;
}
}
return l_undef;
m_optsmt.update_lower(obj.m_index, value);
m_optsmt.update_upper(obj.m_index, value);
}
return result;
}
}

3
src/opt/optsmt.h
View file

@ -61,7 +61,9 @@ namespace opt {
void get_model(model_ref& mdl, svector<symbol>& labels);
model* get_model(unsigned index) const { return m_models[index]; }
void update_lower(unsigned idx, inf_eps const& r);
void update_upper(unsigned idx, inf_eps const& r);
void reset();
@ -82,6 +84,7 @@ namespace opt {
lbool update_upper();
};
};

54
src/qe/qe_arith.cpp
View file

@ -966,9 +966,10 @@ namespace qe {
typedef opt::model_based_opt::var var;
typedef vector<var> vars;
opt::bound_type maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& value, expr_ref& bound) {
opt::model_based_opt mbo;
opt::inf_eps maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& bound) {
opt::model_based_opt mbo;
opt::inf_eps value;
obj_map<expr, rational> ts;
obj_map<expr, unsigned> tids;
vars coeffs;
@ -981,21 +982,40 @@ namespace qe {
linearize(mdl, mbo, fmls[i], tids);
}
rational val;
opt::bound_type result = mbo.maximize(val);
value = a.mk_numeral(val, false);
switch (result) {
case opt::unbounded:
value = mbo.maximize();
expr_ref val(a.mk_numeral(value.get_rational(), false), m);
if (!value.is_finite()) {
bound = m.mk_false();
break;
case opt::strict:
bound = a.mk_le(value, t);
break;
case opt::non_strict:
bound = a.mk_lt(value, t);
break;
return value;
}
return result;
// update model
ptr_vector<expr> vars;
obj_map<expr, unsigned>::iterator it = tids.begin(), end = tids.end();
for (; it != end; ++it) {
expr* e = it->m_key;
if (is_uninterp_const(e)) {
unsigned id = it->m_value;
func_decl* f = to_app(e)->get_decl();
expr_ref val(a.mk_numeral(mbo.get_value(id), false), m);
mdl.register_decl(f, val);
}
else {
TRACE("qe", tout << "omitting model update for non-uninterpreted constant " << mk_pp(e, m) << "\n";);
}
}
if (value.get_infinitesimal().is_neg()) {
bound = a.mk_le(val, t);
}
else {
bound = a.mk_lt(val, t);
}
return value;
}
void extract_coefficients(obj_map<expr, rational> const& ts, obj_map<expr, unsigned>& tids, vars& coeffs) {
@ -1033,8 +1053,8 @@ namespace qe {
return m_imp->a.get_family_id();
}
opt::bound_type arith_project_plugin::maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& value, expr_ref& bound) {
return m_imp->maximize(fmls, mdl, t, value, bound);
opt::inf_eps arith_project_plugin::maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& bound) {
return m_imp->maximize(fmls, mdl, t, bound);
}
bool arith_project(model& model, app* var, expr_ref_vector& lits) {

3
src/qe/qe_arith.h
View file

@ -29,7 +29,8 @@ namespace qe {
virtual bool operator()(model& model, app* var, app_ref_vector& vars, expr_ref_vector& lits);
virtual bool solve(model& model, app_ref_vector& vars, expr_ref_vector& lits);
virtual family_id get_family_id();
opt::bound_type maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& value, expr_ref& bound);
opt::inf_eps maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& bound);
};
bool arith_project(model& model, app* var, expr_ref_vector& lits);

8
src/qe/qe_mbp.cpp
View file

@ -213,9 +213,9 @@ class mbp::impl {
public:
opt::bound_type maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& value, expr_ref& bound) {
opt::inf_eps maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& bound) {
arith_project_plugin arith(m);
return arith.maximize(fmls, mdl, t, value, bound);
return arith.maximize(fmls, mdl, t, bound);
}
void extract_literals(model& model, expr_ref_vector& fmls) {
@ -421,6 +421,6 @@ void mbp::extract_literals(model& model, expr_ref_vector& lits) {
m_impl->extract_literals(model, lits);
}
opt::bound_type mbp::maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& value, expr_ref& bound) {
return m_impl->maximize(fmls, mdl, t, value, bound);
opt::inf_eps mbp::maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& bound) {
return m_impl->maximize(fmls, mdl, t, bound);
}

2
src/qe/qe_mbp.h
View file

@ -76,7 +76,7 @@ namespace qe {
\brief
Maximize objective t under current model for constraints in fmls.
*/
opt::bound_type maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& value, expr_ref& bound);
opt::inf_eps maximize(expr_ref_vector const& fmls, model& mdl, app* t, expr_ref& bound);
};
}

18
src/qe/qsat.cpp
View file

@ -1162,8 +1162,7 @@ namespace qe {
m_level(0),
m_mode(mode),
m_avars(m),
m_free_vars(m),
m_value(m)
m_free_vars(m)
{
reset();
}
@ -1283,17 +1282,15 @@ namespace qe {
}
app* m_objective;
expr_ref m_value;
opt::bound_type m_bound;
opt::inf_eps m_value;
bool m_was_sat;
lbool maximize(expr_ref_vector const& fmls, app* t, expr_ref& value, opt::bound_type& bound) {
lbool maximize(expr_ref_vector const& fmls, app* t, opt::inf_eps& value) {
expr_ref_vector defs(m);
expr_ref fml = negate_core(fmls);
hoist(fml);
m_objective = t;
m_value = 0;
m_bound = opt::unbounded;
m_value = opt::inf_eps();
m_was_sat = false;
m_pred_abs.abstract_atoms(fml, defs);
fml = m_pred_abs.mk_abstract(fml);
@ -1319,7 +1316,6 @@ namespace qe {
throw tactic_exception(s.c_str());
}
value = m_value;
bound = m_bound;
return l_true;
}
@ -1327,16 +1323,16 @@ namespace qe {
TRACE("qe", tout << "maximize: " << core << "\n";);
m_was_sat |= !core.empty();
expr_ref bound(m);
m_bound = m_mbp.maximize(core, mdl, m_objective, m_value, bound);
m_value = m_mbp.maximize(core, mdl, m_objective, bound);
m_ex.assert_expr(bound);
}
};
lbool maximize(expr_ref_vector const& fmls, app* t, expr_ref& value, opt::bound_type& bound, params_ref const& p) {
lbool maximize(expr_ref_vector const& fmls, app* t, opt::inf_eps& value, params_ref const& p) {
ast_manager& m = fmls.get_manager();
qsat qs(m, p, qsat_maximize);
return qs.maximize(fmls, t, value, bound);
return qs.maximize(fmls, t, value);
}
};

2
src/qe/qsat.h
View file

@ -114,7 +114,7 @@ namespace qe {
void collect_statistics(statistics& st) const;
};
lbool maximize(expr_ref_vector const& fmls, app* t, expr_ref& value, opt::bound_type& bound, params_ref const& p);
lbool maximize(expr_ref_vector const& fmls, app* t, opt::inf_eps& value, params_ref const& p);
}

1
src/util/inf_eps_rational.h
View file

@ -23,6 +23,7 @@ Revision History:
#include"debug.h"
#include"vector.h"
#include"rational.h"
#include"inf_rational.h"
template<typename Numeral>
class inf_eps_rational {