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demonstration of theory-aware branching in theory_str, WIP

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This commit is contained in:
Murphy Berzish 2017-01-10 19:50:46 -05:00
parent 3459c1993e
commit 1363f50e4f
4 changed files with 29 additions and 23 deletions
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4
src/smt/smt_context.cpp
View file

@ -2999,6 +2999,10 @@ namespace smt {
}
}
void context::add_theory_aware_branching_info(bool_var v, double priority, lbool phase) {
m_case_split_queue->add_theory_aware_branching_info(v, priority, phase);
}
void context::undo_th_case_split(literal l) {
m_all_th_case_split_literals.remove(l.index());
if (m_literal2casesplitsets.contains(l.index())) {

7
src/smt/smt_context.h
View file

@ -825,6 +825,13 @@ namespace smt {
*/
void mk_th_case_split(unsigned num_lits, literal * lits);
/*
* Provide a hint to the branching heuristic about the priority of a "theory-aware literal".
* Literals marked in this way will always be branched on before unmarked literals,
* starting with the literal having the highest priority.
*/
void add_theory_aware_branching_info(bool_var v, double priority, lbool phase);
// helper function for trail
void undo_th_case_split(literal l);

40
src/smt/theory_str.cpp
View file

@ -2501,6 +2501,13 @@ void theory_str::infer_len_concat_equality(expr * nn1, expr * nn2) {
*/
}
void theory_str::add_theory_aware_branching_info(expr * term, double priority, lbool phase) {
context & ctx = get_context();
ctx.internalize(term, false);
bool_var v = ctx.get_bool_var(term);
ctx.add_theory_aware_branching_info(v, priority, phase);
}
void theory_str::generate_mutual_exclusion(expr_ref_vector & terms) {
context & ctx = get_context();
// pull each literal out of the arrangement disjunction
@ -2512,25 +2519,6 @@ void theory_str::generate_mutual_exclusion(expr_ref_vector & terms) {
ls.push_back(l);
}
ctx.mk_th_case_split(ls.size(), ls.c_ptr());
// old version, without special support in the context
/*
ast_manager & m = get_manager();
expr_ref_vector result(m);
for (unsigned int majorIndex = 0; majorIndex < terms.size(); ++majorIndex) {
for (unsigned int minorIndex = majorIndex + 1; minorIndex < terms.size(); ++minorIndex) {
// generate an expression of the form
// terms[majorIndex] --> NOT(terms[minorIndex])
expr_ref ex(rewrite_implication(terms.get(majorIndex), m.mk_not(terms.get(minorIndex))), m);
result.push_back(ex);
}
}
expr_ref final_result(mk_and(result), m);
assert_axiom(final_result);
*/
}
void theory_str::print_cut_var(expr * node, std::ofstream & xout) {
@ -3095,7 +3083,9 @@ void theory_str::process_concat_eq_type1(expr * concatAst1, expr * concatAst2) {
m_autil.mk_add(mk_strlen(y),m_autil.mk_mul(mk_int(-1), mk_strlen(n))),
mk_int(0))) );
arrangement_disjunction.push_back(mk_and(and_item));
expr_ref option1(mk_and(and_item), mgr);
arrangement_disjunction.push_back(option1);
add_theory_aware_branching_info(option1, 0.0, l_true);
add_cut_info_merge(t1, ctx.get_scope_level(), m);
add_cut_info_merge(t1, ctx.get_scope_level(), y);
@ -3130,8 +3120,9 @@ void theory_str::process_concat_eq_type1(expr * concatAst1, expr * concatAst2) {
m_autil.mk_add(mk_strlen(n), m_autil.mk_mul(mk_int(-1), mk_strlen(y))),
mk_int(0))) );
arrangement_disjunction.push_back(mk_and(and_item));
expr_ref option2(mk_and(and_item), mgr);
arrangement_disjunction.push_back(option2);
add_theory_aware_branching_info(option2, 0.0, l_true);
add_cut_info_merge(t2, ctx.get_scope_level(), x);
add_cut_info_merge(t2, ctx.get_scope_level(), n);
@ -3149,7 +3140,10 @@ void theory_str::process_concat_eq_type1(expr * concatAst1, expr * concatAst2) {
and_item.push_back(ctx.mk_eq_atom(mk_strlen(x), mk_strlen(m)));
and_item.push_back(ctx.mk_eq_atom(mk_strlen(y), mk_strlen(n)));
arrangement_disjunction.push_back(mk_and(and_item));
expr_ref option3(mk_and(and_item), mgr);
arrangement_disjunction.push_back(option3);
// prioritize this case, it is easier
add_theory_aware_branching_info(option3, 2.0, l_true);
}
if (!arrangement_disjunction.empty()) {

1
src/smt/theory_str.h
View file

@ -500,6 +500,7 @@ namespace smt {
void print_cut_var(expr * node, std::ofstream & xout);
void generate_mutual_exclusion(expr_ref_vector & exprs);
void add_theory_aware_branching_info(expr * term, double priority, lbool phase);
bool new_eq_check(expr * lhs, expr * rhs);
void group_terms_by_eqc(expr * n, std::set<expr*> & concats, std::set<expr*> & vars, std::set<expr*> & consts);