Function MakeQuantizedColumn

catboost/libs/data/quantization.cpp:1041–1088

        class TSrc,
        class TDst>
    static void MakeQuantizedColumn(
        const TSrc& srcFeature,
        const TQuantizedFeaturesInfo& quantizedFeaturesInfo,
        const TIncrementalDenseIndexing& incrementalDenseIndexing,
        ESparseArrayIndexingType sparseArrayIndexingType,
        const TFeaturesArraySubsetIndexing* dstSubsetIndexing,
        NPar::ILocalExecutor* localExecutor,

        // pass as parameter to enable type deduction
        THolder<TDst>* dstFeature
    ) {
        TValueQuantizer<TSrc> valueQuantizer(quantizedFeaturesInfo, srcFeature.GetId());

        // dispatch by storedDstValueType
        auto makeQuantizedColumnForStoredDstValue = [&] (auto storedDstValueExample) {
            if (valueQuantizer.GetDefaultBin()) {
                MakeQuantizedColumnWithDefaultBin<decltype(storedDstValueExample)>(
                    srcFeature,
                    std::move(valueQuantizer),
                    sparseArrayIndexingType,
                    dstFeature
                );
            } else {
                MakeQuantizedColumnWithoutDefaultBin<decltype(storedDstValueExample)>(
                    srcFeature,
                    incrementalDenseIndexing,
                    std::move(valueQuantizer),
                    dstSubsetIndexing,
                    localExecutor,
                    dstFeature
                );
            }
        };

        switch (valueQuantizer.GetDstBitsPerKey()) {
            case 8:
                makeQuantizedColumnForStoredDstValue(ui8());
                break;
            case 16:
                makeQuantizedColumnForStoredDstValue(ui16());
                break;
            case 32:
                makeQuantizedColumnForStoredDstValue(ui32());
                break;
            default:
                CB_ENSURE_INTERNAL(false, "MakeQuantizedColumn: unsupported bits per key");
        }
    }

    TMaybe<ui32> GetDefaultQuantizedValue(
        const TQuantizedFeaturesInfo& quantizedFeaturesInfo,