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interpolation fix and improving duality quantifier handling

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This commit is contained in:
Ken McMillan 2014-04-01 17:10:14 -07:00
parent 732035bf63
commit 6c9483c70a
5 changed files with 86 additions and 19 deletions
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36
src/interp/iz3proof_itp.cpp
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@ -814,6 +814,10 @@ class iz3proof_itp_impl : public iz3proof_itp {
ast equa = sep_cond(arg(pf,0),cond);
if(is_equivrel_chain(equa)){
ast lhs,rhs; eq_from_ineq(arg(neg_equality,0),lhs,rhs); // get inequality we need to prove
if(!rewrites_from_to(equa,lhs,rhs)){
lhs = arg(arg(neg_equality,0),0); // the equality proved is ambiguous, sadly
rhs = arg(arg(neg_equality,0),1);
}
LitType lhst = get_term_type(lhs), rhst = get_term_type(rhs);
if(lhst != LitMixed && rhst != LitMixed)
return unmixed_eq2ineq(lhs, rhs, op(arg(neg_equality,0)), equa, cond);
@ -1671,9 +1675,20 @@ class iz3proof_itp_impl : public iz3proof_itp {
return head;
}
// split a rewrite chain into head and tail at last non-mixed term
bool has_mixed_summands(const ast &e){
if(op(e) == Plus){
int nargs = num_args(e);
for(int i = 0; i < nargs; i++)
if(has_mixed_summands(arg(e,i)))
return true;
return false;
}
return get_term_type(e) == LitMixed;
}
// split a rewrite chain into head and tail at last sum with no mixed sumands
ast get_right_movers(const ast &chain, const ast &rhs, ast &tail, ast &mid){
if(is_true(chain) || get_term_type(rhs) != LitMixed){
if(is_true(chain) || !has_mixed_summands(rhs)){
mid = rhs;
tail = mk_true();
return chain;
@ -1686,11 +1701,11 @@ class iz3proof_itp_impl : public iz3proof_itp {
return res;
}
// split a rewrite chain into head and tail at first non-mixed term
// split a rewrite chain into head and tail at first sum with no mixed sumands
ast get_left_movers(const ast &chain, const ast &lhs, ast &tail, ast &mid){
if(is_true(chain)){
mid = lhs;
if(get_term_type(lhs) != LitMixed){
if(!has_mixed_summands(lhs)){
tail = mk_true();
return chain;
}
@ -1790,10 +1805,21 @@ class iz3proof_itp_impl : public iz3proof_itp {
}
bool rewrites_from_to(const ast &chain, const ast &lhs, const ast &rhs){
if(is_true(chain))
return lhs == rhs;
ast last = chain_last(chain);
ast rest = chain_rest(chain);
ast mid = subst_in_pos(rhs,rewrite_pos(last),rewrite_lhs(last));
return rewrites_from_to(rest,lhs,mid);
}
struct bad_ineq_inference {};
ast chain_ineqs(opr comp_op, LitType t, const ast &chain, const ast &lhs, const ast &rhs){
if(is_true(chain)){
if(lhs != rhs)
throw "bad ineq inference";
throw bad_ineq_inference();
return make(Leq,make_int(rational(0)),make_int(rational(0)));
}
ast last = chain_last(chain);