Function GetBucketCount

catboost/private/libs/algo/split.cpp:89–136

int GetBucketCount(
    const TSplitEnsemble& splitEnsemble,
    const NCB::TQuantizedFeaturesInfo& quantizedFeaturesInfo,
    size_t packedBinaryFeaturesCount,
    TConstArrayRef<NCB::TExclusiveFeaturesBundle> exclusiveFeaturesBundles,
    TConstArrayRef<NCB::TFeaturesGroup> featuresGroups
) {
    switch (splitEnsemble.Type) {
        case ESplitEnsembleType::OneFeature:
            // TSplitCandidate
            {
                const auto& splitCandidate = splitEnsemble.SplitCandidate;
                if (splitCandidate.Type == ESplitType::OnlineCtr) {
                    return splitCandidate.Ctr.BorderCount + 1;
                } else if ((splitCandidate.Type == ESplitType::FloatFeature) ||
                           (splitCandidate.Type == ESplitType::EstimatedFeature))
                {
                    return int(
                        quantizedFeaturesInfo.GetBorders(TFloatFeatureIdx(splitCandidate.FeatureIdx)).size()
                    ) + 1;
                } else {
                    Y_ASSERT(splitCandidate.Type == ESplitType::OneHotFeature);
                    return int(
                        quantizedFeaturesInfo.GetUniqueValuesCounts(TCatFeatureIdx(splitCandidate.FeatureIdx))
                            .OnLearnOnly
                    );
                }
            }
        case ESplitEnsembleType::BinarySplits:
            {
                size_t packIdx = splitEnsemble.BinarySplitsPackRef.PackIdx;
                size_t startIdx = packIdx * sizeof(TBinaryFeaturesPack) * CHAR_BIT;
                Y_ASSERT(packedBinaryFeaturesCount > startIdx);
                size_t featuresInPackCount = Min(
                    sizeof(TBinaryFeaturesPack) * CHAR_BIT,
                    packedBinaryFeaturesCount - startIdx
                );
                return int(1u << featuresInPackCount);
            }
        case ESplitEnsembleType::ExclusiveBundle:
            return exclusiveFeaturesBundles[splitEnsemble.ExclusiveFeaturesBundleRef.BundleIdx].GetBinCount();
        case ESplitEnsembleType::FeaturesGroup:
            return featuresGroups[splitEnsemble.FeaturesGroupRef.GroupIdx].TotalBucketCount;
        default:
            CB_ENSURE(false, "Unexpected split ensemble type");
    }
    Y_UNREACHABLE();
}