static void add_ineq(opt::model_based_opt& mbo,
unsigned x, int a,
unsigned y, int b, int k,
opt::ineq_type rel) {
vector<var> vars;
vars.push_back(var(x, rational(a)));
vars.push_back(var(y, rational(b)));
mbo.add_constraint(vars, rational(k), rel);
}
static void add_random_ineq(opt::model_based_opt& mbo,
random_gen& r,
svector<int> const& values,
unsigned max_vars,
unsigned max_coeff) {
unsigned num_vars = values.size();
uint_set used_vars;
vector<var> vars;
int value = 0;
for (unsigned i = 0; i < max_vars; ++i) {
unsigned x = r(num_vars);
if (used_vars.contains(x)) {
continue;
}
used_vars.insert(x);
int coeff = r(max_coeff + 1);
if (coeff == 0) {
continue;
}
unsigned sign = r(2);
coeff = sign == 0 ? coeff : -coeff;
vars.push_back(var(x, rational(coeff)));
value += coeff*values[x];
}
unsigned abs_value = value < 0 ? - value : value;
// value + k <= 0
// k <= - value
// range for k is 2*|value|
// k <= - value - range
opt::ineq_type rel = opt::t_le;
int coeff = 0;
if (r(4) == 0) {
rel = opt::t_eq;
coeff = -value;
}
else {
if (abs_value > 0) {
coeff = -value - r(2*abs_value);
}
else {
coeff = 0;
}
if (coeff != -value && r(3) == 0) {
rel = opt::t_lt;
}
}
mbo.add_constraint(vars, rational(coeff), rel);
}
static void add_random_ineq(
expr_ref_vector& fmls,
opt::model_based_opt& mbo,
random_gen& r,
svector<int> const& values,
unsigned max_vars,
unsigned max_coeff)
{
ast_manager& m = fmls.get_manager();
arith_util a(m);
unsigned num_vars = values.size();
uint_set used_vars;
vector<var_t> vars;
int value = 0;
for (unsigned i = 0; i < max_vars; ++i) {
unsigned x = r(num_vars);
if (used_vars.contains(x)) {
continue;
}
used_vars.insert(x);
int coeff = r(max_coeff + 1);
if (coeff == 0) {
continue;
}
unsigned sign = r(2);
coeff = sign == 0 ? coeff : -coeff;
vars.push_back(var_t(x, rational(coeff)));
value += coeff*values[x];
}
unsigned abs_value = value < 0 ? - value : value;
// value + k <= 0
// k <= - value
// range for k is 2*|value|
// k <= - value - range
opt::ineq_type rel = opt::t_le;
int coeff = 0;
if (r(4) == 0) {
rel = opt::t_eq;
coeff = -value;
}
else {
if (abs_value > 0) {
coeff = -value - r(2*abs_value);
}
else {
coeff = 0;
}
if (coeff != -value && r(3) == 0) {
rel = opt::t_lt;
}
}
expr_ref fml(m);
app_ref t1(m);
app_ref t2(a.mk_numeral(rational(0), a.mk_real()), m);
mk_term(vars, rational(coeff), t1);
switch (rel) {
case opt::t_eq:
fml = m.mk_eq(t1, t2);
break;
case opt::t_lt:
fml = a.mk_lt(t1, t2);
break;
case opt::t_le:
fml = a.mk_le(t1, t2);
break;
case opt::t_mod:
NOT_IMPLEMENTED_YET();
break;
}
fmls.push_back(fml);
mbo.add_constraint(vars, rational(coeff), rel);
}