Function RegularBorder

library/cpp/grid_creator/binarization.cpp:698–731

Border before element with value "border"

// Border before element with value "border"
static float RegularBorder(float border, const TVector<float>& sortedValues, const TMaybe<TVector<float>>& initialBorders) {
    TVector<float>::const_iterator lowerBound = LowerBound(sortedValues.begin(), sortedValues.end(), border);

    if (lowerBound == sortedValues.end()) { // binarizing to always false
        if (initialBorders && !initialBorders->empty()) {
            if (sortedValues.back() < initialBorders->back()) {
                return initialBorders->back();
            }
        }
        return Max(2.f * sortedValues.back(), sortedValues.back() + 1.f);
    }

    if (lowerBound == sortedValues.begin()) {// binarizing to always true
        if (initialBorders && !initialBorders->empty()) {
            if ((*initialBorders)[0] <= sortedValues.back()) {
                return (*initialBorders)[0];
            }
        }
        return Min(.5f * sortedValues.front(), 2.f * sortedValues.front());
    }

    if (initialBorders) {
        const auto possibleBorder = UpperBound(initialBorders->begin(), initialBorders->end(), lowerBound[-1]);
        if (possibleBorder != initialBorders->end() && (*possibleBorder) <= lowerBound[0]) {
            return (*possibleBorder);
        }
    }

    float res = (lowerBound[0] + lowerBound[-1]) * .5f;
    if (res == lowerBound[0]) { // wrong side rounding (should be very scarce)
        res = lowerBound[-1];
    }
    return res;
}


namespace {