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working on expansion

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2012-10-17 08:34:42 -07:00
parent 3a837037d4
commit 8459401b6e
7 changed files with 198 additions and 212 deletions
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59
lib/pdr_context.cpp
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@ -1303,9 +1303,6 @@ namespace pdr {
else {
m_model_generalizers.push_back(alloc(model_evaluation_generalizer, *this, m));
}
if (m_params.get_bool(":use-farkas-model", false)) {
m_model_generalizers.push_back(alloc(model_farkas_generalizer, *this));
}
if (m_params.get_bool(":use-precondition-generalizer", false)) {
m_model_generalizers.push_back(alloc(model_precond_generalizer, *this));
}
@ -1689,32 +1686,60 @@ namespace pdr {
Goal is to find phi0(x0), phi1(x1) such that:
phi(x) & phi0(x0) & phi1(x1) => psi(x0, x1, x)
phi(x) & phi0(x0) & phi1(x1) => psi(x0, x1, x)
or at least (ignoring psi alltogether):
phi(x) & phi0(x0) & phi1(x1) => T(x0, x1, x)
Strategy:
- perform cheap existential quantifier elimination on
exists x . T(x0,x1,x) & phi(x)
(e.g., destructive equality resolution)
- Extract literals from T & phi using ternary simulation with M.
- resulting formula is Phi.
- perform cheap existential quantifier elimination on
Phi <- exists x . Phi(x0,x1,x)
(e.g., destructive equality resolution)
- Sub-strategy 1: rename remaining x to fresh variables.
- Sub-strategy 2: replace remaining x to M(x).
- For each literal L in result:
- if L is x0 pure, add L to L0
- if L is x1 pure, add L to L1
- if L mixes x0, x1, add x1 = M(x1) to L1, add L(x1 |-> M(x1)) to L0
- Create sub-goals for L0 and L1.
- pull equalities that use
*/
void context::create_children2(model_node& n, expr* psi) {
SASSERT(n.level() > 0);
pred_transformer& pt = n.pt();
model_core const& M = n.model();
datalog::rule const& r = n.pt().find_rule(M);
expr* T = n.pt().get_transition(r);
datalog::rule const& r = pt.find_rule(M);
expr* T = pt.get_transition(r);
expr* phi = n.state();
expr_ref_vector Ts(m);
datalog::flatten_and(T, Ts);
ternary_model_evaluator tmev(m);
expr_ref_vector mdl(m);
ptr_vector<expr> forms;
forms.push_back(T);
forms.push_back(phi);
datalog::flatten_and(psi, mdl);
expr_ref_vector Phi = tmev.minimize_literals(forms, mdl);
ptr_vector<func_decl> preds;
n.pt().find_predecessors(r, preds);
n.pt().remove_predecessors(Ts);
pt.find_predecessors(r, preds);
pt.remove_predecessors(Phi);
expr_ref_vector vars(m);
unsigned sig_size = pt.head()->get_arity();
for (unsigned i = 0; i < sig_size; ++i) {
vars.push_back(m.mk_const(m_pm.o2n(pt.sig(i), 0)));
}
// TBD: reduce_vars(vars, Phi);
// TBD ...
TRACE("pdr", m_search.display(tout););