diff options
author | Andrew Reynolds <andrew.j.reynolds@gmail.com> | 2020-07-02 08:33:49 -0500 |
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committer | GitHub <noreply@github.com> | 2020-07-02 08:33:49 -0500 |
commit | 5401565e7622f9ee6b07abb68e1a9378cb9876a8 (patch) | |
tree | 6aec7ada59563bdd8ecad7b78dbe4ab6d3014a3c /src/expr/skolem_manager.cpp | |
parent | 5266e8e075ed222598449cb7bc058e095077d3ae (diff) |
(proof-new) Updates to skolem manager interface (#4664)
Adds a fix for mkPurifySkolem and introduces new interfaces in preparation for arithmetic operator elimination and term formula removal proofs.
Diffstat (limited to 'src/expr/skolem_manager.cpp')
-rw-r--r-- | src/expr/skolem_manager.cpp | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/src/expr/skolem_manager.cpp b/src/expr/skolem_manager.cpp index 99f252530..e22bd26cf 100644 --- a/src/expr/skolem_manager.cpp +++ b/src/expr/skolem_manager.cpp @@ -15,6 +15,7 @@ #include "expr/skolem_manager.h" #include "expr/attribute.h" +#include "expr/node_algorithm.h" using namespace CVC4::kind; @@ -42,7 +43,8 @@ Node SkolemManager::mkSkolem(Node v, const std::string& prefix, const std::string& comment, int flags, - ProofGenerator* pg) + ProofGenerator* pg, + bool retWitness) { Assert(v.getKind() == BOUND_VARIABLE); // make the witness term @@ -55,12 +57,20 @@ Node SkolemManager::mkSkolem(Node v, // store the mapping to proof generator if it exists if (pg != nullptr) { - Node q = nm->mkNode(EXISTS, w[0], w[1]); + // We cache based on the original (Skolem) form, since the user of this + // method operates on Skolem forms. + Node q = nm->mkNode(EXISTS, bvl, pred); // Notice this may overwrite an existing proof generator. This does not // matter since either should be able to prove q. d_gens[q] = pg; } - return getOrMakeSkolem(w, prefix, comment, flags); + Node k = getOrMakeSkolem(w, prefix, comment, flags); + // if we want to return the witness term, make it + if (retWitness) + { + return nm->mkNode(WITNESS, bvl, pred); + } + return k; } Node SkolemManager::mkSkolemize(Node q, @@ -159,7 +169,7 @@ Node SkolemManager::mkPurifySkolem(Node t, // directly. if (t.getKind() == WITNESS) { - return getOrMakeSkolem(t, prefix, comment, flags); + return getOrMakeSkolem(getWitnessForm(t), prefix, comment, flags); } Node v = NodeManager::currentNM()->mkBoundVar(t.getType()); Node k = mkSkolem(v, v.eqNode(t), prefix, comment, flags); @@ -167,6 +177,11 @@ Node SkolemManager::mkPurifySkolem(Node t, return k; } +Node SkolemManager::mkBooleanTermVariable(Node t) +{ + return mkPurifySkolem(t, "", "", NodeManager::SKOLEM_BOOL_TERM_VAR); +} + Node SkolemManager::mkExistential(Node t, Node p) { Assert(p.getType().isBoolean()); @@ -275,7 +290,9 @@ Node SkolemManager::convertInternal(Node n, bool toWitness) // called on them. Regardless, witness terms with free variables // should never be themselves assigned skolems (otherwise we would have // assertions with free variables), and thus they can be treated like - // ordinary terms here. + // ordinary terms here. We use an assertion to check that this is + // indeed the case. + Assert(cur.getKind() != WITNESS || expr::hasFreeVar(cur)); cur.setAttribute(sfa, ret); } visited[cur] = ret; @@ -316,7 +333,16 @@ Node SkolemManager::getOrMakeSkolem(Node w, } NodeManager* nm = NodeManager::currentNM(); // make the new skolem - Node k = nm->mkSkolem(prefix, w.getType(), comment, flags); + Node k; + if (flags & NodeManager::SKOLEM_BOOL_TERM_VAR) + { + Assert (w.getType().isBoolean()); + k = nm->mkBooleanTermVariable(); + } + else + { + k = nm->mkSkolem(prefix, w.getType(), comment, flags); + } // set witness form attribute for k WitnessFormAttribute wfa; k.setAttribute(wfa, w); |