ReasoningMode Reasoner::chooseMostEfficientAlgo(Literal &query,
EDBLayer &layer, Program &program,
std::vector<uint8_t> *posBindings,
std::vector<Term_t> *valueBindings) {
uint64_t cost = 0;
if (posBindings != NULL) {
//Create a new pattern with the values substituted
int idxValues = 0;
VTuple newTuple = query.getTuple();
for (std::vector<uint8_t>::iterator itr = posBindings->begin(); itr != posBindings->end();
++itr) {
newTuple.set(VTerm(0, valueBindings->at(idxValues)), *itr);
idxValues++;
}
Literal newLiteral(query.getPredicate(), newTuple);
size_t singleCost = estimate(newLiteral, NULL, NULL, layer, program);
BOOST_LOG_TRIVIAL(debug) << "SingleCost is " <<
singleCost << " nBindings " << (valueBindings->size() / posBindings->size());
//Are bindings less than 10? Then singleCost is probably about right
uint64_t nValues = valueBindings->size() / posBindings->size();
if (nValues > 10) {
//Copy the first 10 values
std::vector<Term_t> limitedValueBindings;
for (int i = 0; i < 10 * posBindings->size(); ++i) {
limitedValueBindings.push_back(valueBindings->at(i));
}
uint64_t tenCost = estimate(query, posBindings,
&limitedValueBindings, layer, program);
BOOST_LOG_TRIVIAL(debug) << "TenCost is " << tenCost;
//y = mx + b. m is slope, b is constant.
//I assume the singleCost is the cost at position 0. Otherwise it's not a line
double m = (double)(tenCost - singleCost) / (10); // 9? --Ceriel
long b = singleCost;
cost = (uint64_t) (m * nValues + b);
} else {
cost = singleCost;
}
} else {
cost = estimate(query, NULL, NULL, layer, program);
}
ReasoningMode mode = cost < threshold ? TOPDOWN : MAGIC;
BOOST_LOG_TRIVIAL(debug) << "Deciding whether I should resolve " <<
query.tostring(&program, &layer) << " with magic or QSQR. Estimated cost: " <<
cost << " threshold for QSQ-R is " << threshold;
return mode;
}
bool CNFGenerator::OnePersonOneTable()
{
Clause onePersonAtLeastOneTable;
Clause onePersonAtMaxOneTable;
for (int i =0;i<people;i++)
{
onePersonAtLeastOneTable.clear();
onePersonAtMaxOneTable.clear();
//cout <<"atleast 1 =";
for (int j=0;j<tables;j++)
{
Literal newLiteral(i,j,false);
//cout <<newLiteral;
onePersonAtLeastOneTable.insert(newLiteral);
}
//cout<<endl;
//sort(onePersonAtLeastOneTable.begin(),onePersonAtLeastOneTable.end());
SetOfClauses.insert(pair<Clause,int> (onePersonAtLeastOneTable,++CNFGenerator::globalClauseCount));
for (int j=0;j<tables;j++)
{
for (int k=j+1;k<tables;k++)
{
onePersonAtMaxOneTable.clear();
Literal newLiteral1(i,j,true);
Literal newLiteral2(i,k,true);
onePersonAtMaxOneTable.insert(newLiteral1);
onePersonAtMaxOneTable.insert(newLiteral2);
//sort(onePersonAtMaxOneTable.begin(),onePersonAtMaxOneTable.end());
SetOfClauses.insert(pair<Clause,int> (onePersonAtMaxOneTable,++CNFGenerator::globalClauseCount));
}
}
}
return true;
}