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add more simplifiers, fix model reconstruction order for elim_unconstrained

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- enable sat.smt in smt_tactic that
is invoked by default on first goals
add flatten-clauses
add push-ite
have tptp5 front-end pretty print SMT2 formulas a little nicer.
This commit is contained in:
Nikolaj Bjorner 2022-12-01 02:35:43 +09:00
parent edb0fc394b
commit cfc8e19baf
10 changed files with 271 additions and 54 deletions
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45
src/math/simplex/model_based_opt.cpp
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@ -1014,12 +1014,14 @@ namespace opt {
return dst;
}
// -x + lo <= 0
void model_based_opt::add_lower_bound(unsigned x, rational const& lo) {
vector<var> coeffs;
coeffs.push_back(var(x, rational::minus_one()));
add_constraint(coeffs, lo, t_le);
}
// x - hi <= 0
void model_based_opt::add_upper_bound(unsigned x, rational const& hi) {
vector<var> coeffs;
coeffs.push_back(var(x, rational::one()));
@ -1442,8 +1444,9 @@ namespace opt {
for (unsigned ri : mod_rows) {
rational a = get_coefficient(ri, x);
replace_var(ri, x, rational::zero());
rational rMod = m_rows[ri].m_mod;
// add w = b mod K
// add w = b mod rMod
vector<var> coeffs = m_rows[ri].m_vars;
rational coeff = m_rows[ri].m_coeff;
unsigned v = m_rows[ri].m_id;
@ -1451,16 +1454,43 @@ namespace opt {
unsigned w = UINT_MAX;
rational offset(0);
if (coeffs.empty() || K == 1)
offset = mod(coeff, K);
if (coeffs.empty() || rMod == 1)
offset = mod(coeff, rMod);
else
w = add_mod(coeffs, coeff, K);
w = add_mod(coeffs, coeff, rMod);
rational w_value = w == UINT_MAX ? offset : m_var2value[w];
// add v = a*z + w - V, for k = (a*z_value + w_value) div K
// claim: (= (mod x K) (- x (* K (div x K)))))) is a theorem for every x, K != 0
#if 1
// V := (a * z_value - w_value) div rMod
// V*rMod <= a*z + w < (V+1)*rMod
// v = a*z + w - V*rMod
SASSERT(a * z_value - w_value >= 0);
rational V = div(a * z_value + w_value, rMod);
vector<var> mod_coeffs;
SASSERT(V >= 0);
SASSERT(a * z_value + w_value >= V*rMod);
SASSERT((V+1)*rMod > a*z_value + w_value);
// -a*z - w + V*rMod <= 0
mod_coeffs.push_back(var(z, -a));
if (w != UINT_MAX) mod_coeffs.push_back(var(w, -rational::one()));
add_constraint(mod_coeffs, V*rMod - offset, t_le);
mod_coeffs.reset();
// a*z + w - (V+1)*rMod + 1 <= 0
mod_coeffs.push_back(var(z, a));
if (w != UINT_MAX) mod_coeffs.push_back(var(w, rational::one()));
add_constraint(mod_coeffs, -(V+1)*rMod + offset + 1, t_le);
mod_coeffs.reset();
// -v + a*z + w - V*rMod = 0
mod_coeffs.push_back(var(v, rational::minus_one()));
mod_coeffs.push_back(var(z, a));
if (w != UINT_MAX) mod_coeffs.push_back(var(w, rational::one()));
add_constraint(mod_coeffs, offset - V*rMod, t_eq);
#else
// add v = a*z + w - V, for V = v_value - a * z_value - w_value
// claim: (= (mod x rMod) (- x (* rMod (div x rMod)))))) is a theorem for every x, rMod != 0
rational V = v_value - a * z_value - w_value;
vector<var> mod_coeffs;
mod_coeffs.push_back(var(v, rational::minus_one()));
@ -1468,7 +1498,8 @@ namespace opt {
if (w != UINT_MAX) mod_coeffs.push_back(var(w, rational::one()));
add_constraint(mod_coeffs, V + offset, t_eq);
add_lower_bound(v, rational::zero());
add_upper_bound(v, K - 1);
add_upper_bound(v, rMod - 1);
#endif
retire_row(ri);
vs.push_back(v);