AnyType
get_row_from_2d_array::run(AnyType & args) {
MappedMatrix input = args[0].getAs<MappedMatrix>();
int index = args[1].getAs<int>() - 1; // database index starts from 1
if (index < 0 or index >= input.cols()) {
std::stringstream err_msg;
err_msg << "Out-of-bound index: " << index << " >= " << input.cols();
throw std::runtime_error(err_msg.str());
}
MutableNativeColumnVector ret(this->allocateArray<double>(input.rows()));
ret = input.col(static_cast<Index>(index));
return ret;
}
void
closestColumnsAndDistances(
const MappedMatrix& inMatrix,
const MappedColumnVector& inVector,
DistanceFunction& inMetric,
RandomAccessIterator ioFirst,
RandomAccessIterator ioLast) {
ReverseLexicographicComparator<
typename std::iterator_traits<RandomAccessIterator>::value_type>
comparator;
std::fill(ioFirst, ioLast,
std::make_tuple(0, std::numeric_limits<double>::infinity()));
for (Index i = 0; i < inMatrix.cols(); ++i) {
double currentDist
= AnyType_cast<double>(
inMetric(MappedColumnVector(inMatrix.col(i)), inVector)
);
// outIndicesAndDistances is a heap, so the first element is maximal
if (currentDist < std::get<1>(*ioFirst)) {
// Unfortunately, the STL does not have a decrease-key function,
// so we are wasting a bit of performance here
std::pop_heap(ioFirst, ioLast, comparator);
*(ioLast - 1) = std::make_tuple(i, currentDist);
std::push_heap(ioFirst, ioLast, comparator);
}
}
std::sort_heap(ioFirst, ioLast, comparator);
}
AnyType matrix_vec_mult_in_mem_2d::run(AnyType & args){
MappedColumnVector vec = args[0].getAs<MappedColumnVector>();
MappedMatrix mat = args[1].getAs<MappedMatrix>();
// Note mat is constructed in the column-first order
// which means that mat is actually transposed
if(vec.size() != mat.cols()){
throw std::invalid_argument(
"dimensions mismatch: vec.size() != matrix.rows()");
};
// trans(vec) * trans(mat) = mat * vec
Matrix r = mat * vec;
ColumnVector v = r.col(0);
return v;
}
std::tuple<Index, double>
closestColumnAndDistance(
const MappedMatrix& inMatrix,
const MappedColumnVector& inVector,
DistanceFunction& inMetric) {
Index closestColumn = 0;
double minDist = std::numeric_limits<double>::infinity();
for (Index i = 0; i < inMatrix.cols(); ++i) {
double currentDist
= AnyType_cast<double>(
inMetric(MappedColumnVector(inMatrix.col(i)), inVector)
);
if (currentDist < minDist) {
closestColumn = i;
minDist = currentDist;
}
}
return std::tuple<Index, double>(closestColumn, minDist);
}