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reasoner.cpp
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reasoner.cpp
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/*
euler.cpp
Created on: Apr 28, 2015
Author: Ohad Asor
*/
#include "reasoner.h"
reasoner::reasoner() : GND ( &predicates[npredicates++].init ( dict.set ( "GND" ) ) ) {}
reasoner::~reasoner() {
delete[] predicates;
delete[] rules;
delete[] frames;
}
rule& rule::init ( predicate* h, predlist b ) {
head = h;
body = b;
return *this;
}
int reasoner::builtin ( predicate* p ) {
if ( p && dict[p->pred] == "GND" ) return 1;
return -1;
}
frame& frame::init ( reasoner* r, const frame& f ) {
if ( r->nframes >= max_frames ) throw "Buffer overflow";
frame& res = init ( r, f.rul, f.src, f.ind, 0, f.substitution, f.ground );
res.parent = f.parent;
return res;
}
frame& frame::init ( reasoner* rs, rule* _r, uint _src, uint _ind, frame* p, subst _s, ground_t _g ) {
if ( rs->nframes >= max_frames ) throw "Buffer overflow";
rul = _r;
src = _src;
ind = _ind;
parent = p;
substitution = _s;
ground = _g;
return *this;
}
void reasoner::printkb() {
static bool pause = false;
cout << endl << "dumping kb with " << npredicates << " predicates, " << nrules << " rules and " << nframes << " frames. " << endl;
cout << "predicates: " << endl;
for ( uint n = 0; n < npredicates; ++n ) cout << predicates[n] << endl;
cout << "rules: " << endl;
for ( uint n = 0; n < nrules; ++n ) cout << rules[n] << endl;
cout << "frames: " << endl;
for ( uint n = 0; n < nframes; ++n ) cout << frames[n] << endl;
if ( pause ) cout << "type <enter> to continue or <c><enter> to stop pausing...";
cout << endl;
if ( pause && getchar() == 'c' ) pause = false;
}
predicate* reasoner::evaluate ( predicate& t, const subst& sub ) {
predicate* r;
trace ( "\tEval " << t << " in " << sub << endl );
if ( t.pred < 0 ) {
auto it = sub.find ( t.pred );
r = it == sub.end() ? 0 : evaluate ( *it->second, sub );
} else if ( t.args.empty() ) r = &t;
else {
predicate *p;
r = &predicates[npredicates++].init ( t.pred );
for ( auto x : t.args )
r->args.emplace_back ( ( p = evaluate ( *x, sub ) ) ? p : &predicates[npredicates++].init ( x->pred ) );
}
#ifdef DEBUF
if ( r )
{ trace ( " returned " << *r << endl ); }
else
{ trace ( " returned 0" << endl ); }
#endif
return r;
}
bool reasoner::unify ( predicate* _s, const subst& ssub, predicate* _d, subst& dsub, bool f ) {
if ( !_s && !_d ) {
trace ( "Match two nulls." << endl );
return true;
}
// if ( !_s ) return _d && _d->pred >= 0; // ??
// if ( !_d ) return _s && _s->pred >= 0; // ??
predicate& s = *_s;
predicate& d = *_d;
trace ( "\tUnify s: " << s << " in " << ( ssub ) << " with " << d << " in " << dsub << endl );
// if (s.pred == d.pred) trace("we have local pred match"<<endl);
predicate* p;
if ( s.pred < 0 ) {
if (( p = evaluate ( s, ssub ) )) return unify ( p, ssub, _d, dsub, f );
else {
trace ( "Match." << endl );
return true;
}
}
if ( d.pred >= 0 ) {
if ( s.pred != d.pred || s.args.size() != d.args.size() ) return false;
const predlist& as = s.args, ad = d.args;
for ( auto sit = as.begin(), dit = ad.begin(); sit != as.end(); ++sit, ++dit )
if ( !unify ( *sit, ssub, *dit, dsub, f ) )
return false;
trace ( "Match." << endl );
return true;
}
p = evaluate ( d, dsub );
if ( ( p = evaluate ( d, dsub ) ) ) return unify ( _s, ssub, p, dsub, f );
if ( f ) dsub[d.pred] = evaluate ( s, ssub );
trace ( "Match with subst: " << dsub << endl );
return true;
}
void reasoner::evidence_found ( const frame& current_frame, evidence_t& evidence ) {
for ( predicate* x : current_frame.rul->body ) {
predicate* t = evaluate ( *x, current_frame.substitution );
evidence[t->pred].emplace_back (/* &rules[nrules++].init (*/ t/*, { mkpred ( "GND" ) } )*/, current_frame.ground );
}
}
frame* reasoner::next_frame ( const frame& current_frame, ground_t& g ) {
if ( !current_frame.rul->body.empty() ) g.emplace_front ( current_frame.rul, current_frame.substitution );
frame& new_frame = frames[nframes++].init ( this, *current_frame.parent );
new_frame.ground = g;
unify ( current_frame.rul->head, current_frame.substitution, new_frame.rul->body[new_frame.ind], new_frame.substitution, true );
new_frame.ind++;
return &new_frame;
}
frame* reasoner::match_cases ( frame& current_frame, predicate& t, cases_t& cases, deque<frame*>& queue ) {
if ( cases.find ( t.pred ) == cases.end() ) return 0;
uint src = 0;
for ( rule* _rl : cases[t.pred] ) {
rule& rl = *_rl;
src++;
ground_t ground = current_frame.ground;
if ( rl.body.empty() )
ground.emplace_back ( &rl, subst() );
frame& candidate_frame = frames[nframes++].init ( this, &rl, src, 0, ¤t_frame, subst(), ground );
if ( unify ( &t, current_frame.substitution, rl.head, candidate_frame.substitution, true ) ) {
trace ( "unification of rule " << rl << " from cases against " << t << " passed" << endl );
frame& ep = current_frame;
while ( ep.parent ) {
ep = *ep.parent;
if ( ( ep.src == current_frame.src ) &&
unify ( ep.rul->head, ep.substitution, current_frame.rul->head, current_frame.substitution, false ) )
break;
}
if ( !ep.parent ) {
// cout << "pushing frame: " << candidate_frame << endl;
// return
queue.push_front(&candidate_frame);
}
} else {
trace ( "unification of rule " << rl << " from cases against " << t << " failed" << endl );
}
}
return 0;
}
evidence_t reasoner::operator() ( rule* goal, int max_steps, cases_t& cases ) {
trace("dict: "<<dict.tostr()<<endl);
deque<frame*> queue;
queue.emplace_back ( &frames[nframes++].init ( this, goal ) );
uint step = 0;
evidence_t evidence;
cout << "goal: " << *goal << endl << "cases:" << endl << cases << endl;
while ( !queue.empty() && ++step ) {
frame& current_frame = *queue.front();
queue.pop_front();
ground_t g = current_frame.ground;
trace ( current_frame << endl );
if ( max_steps != -1 && ( int ) step >= max_steps ) return evidence_t();
if ( current_frame.ind >= current_frame.rul->body.size() ) {
if ( !current_frame.parent ) evidence_found ( current_frame, evidence );
else queue.push_back ( next_frame ( current_frame, g ) );
} else {
predicate* t = current_frame.rul->body[current_frame.ind];
int b = builtin ( t ); // ( t, c );
if ( b == 1 ) {
g.emplace_back ( &rules[nrules++].init ( evaluate ( *t, current_frame.substitution ) ), subst() );
frame& r = frames[nframes++].init ( this, current_frame );
r.ground = g;
r.ind++;
queue.push_back ( &r );
} else if ( !b ) continue;
// if ( frame* f =
match_cases ( current_frame, *t, cases, queue );
// ) ) queue.push_front ( f );
}
}
return evidence;
}
predicate* reasoner::mkpred ( string s, const vector<predicate*>& v ) {
return &predicates[npredicates++].init ( dict.has ( s ) ? dict[s] : dict.set ( s ), v );
}
rule* reasoner::mkrule ( predicate* p, const vector<predicate*>& v ) {
return &rules[nrules++].init ( p, v );
}
predicate* reasoner::triple ( const string& s, const string& p, const string& o ) {
return mkpred ( p, { mkpred ( s ), mkpred ( o ) } );
};
predicate* reasoner::triple ( const jsonld::quad& q ) {
return triple ( q.subj->value, q.pred->value, q.object->value );
};
qlist merge ( const qdb& q ) {
qlist r;
for ( auto x : q ) for ( auto y : *x.second ) r.push_back ( y );
return r;
}
evidence_t reasoner::operator() ( const qdb &kb, const qlist& query ) {
evidence_t evidence;
cases_t cases;
for ( const pair<string, jsonld::pqlist>& x : kb ) {
for ( jsonld::pquad quad : *x.second ) {
const string &s = quad->subj->value, &p = quad->pred->value, &o = quad->object->value, &c = quad->graph->value;
trace("processing quad " << quad->tostring() << endl);
cases[dict[p]].push_back ( mkrule ( triple ( s, p, o ) ) );
if ( p != implication || kb.find ( o ) == kb.end() ) continue;
for ( jsonld::pquad y : *kb.at ( o ) ) {
rule& rul = *mkrule();
rul.head = triple ( *y );
if ( kb.find ( s ) != kb.end() )
for ( jsonld::pquad z : *kb.at ( s ) )
rul.body.push_back ( triple ( *z ) );
cases[rul.head->pred].push_back ( &rul );
trace("added rule " << rul << endl);
}
}
}
rule& goal = *mkrule();
for ( auto q : query ) goal.body.push_back ( triple ( *q ) );
printkb();
return ( *this ) ( &goal, -1, cases );
}
bool reasoner::test_reasoner() {
dict.set ( "a" );
// cout <<"dict:"<<endl<< dict.tostr() << endl;
// exit(0);
evidence_t evidence;
cases_t cases;
typedef predicate* ppredicate;
ppredicate Socrates = mkpred ( "Socrates" ), Man = mkpred ( "Man" ), Mortal = mkpred ( "Mortal" ), Male = mkpred ( "Male" ), _x = mkpred ( "?x" ), _y = mkpred ( "?y" );
cases[dict["a"]].push_back ( mkrule ( mkpred ( "a", {Socrates, Male} ) ) );
cases[dict["a"]].push_back ( mkrule ( mkpred ( "a", {_x, Mortal} ), { mkpred ( "a", {_x, Man } ) } ) );
cases[dict["a"]].push_back ( mkrule ( mkpred ( "a", {_x, Man } ), { mkpred ( "a", {_x, Male} ) } ) );
cout << "cases:" << endl << cases << endl;
predicate* goal = mkpred ( "a", { _y, Mortal } );
evidence = ( *this ) ( mkrule ( 0, { goal } ), -1, cases );
cout << "evidence: " << evidence.size() << " items..." << endl;
cout << evidence << endl;
cout << "QED!" << endl;
cout << evidence.size() << endl;
return evidence.size();
}