Function Shuffle

catboost/cuda/data/data_utils.h:22–47

    template <class TIndicesType>
    inline void Shuffle(ui64 seed, ui32 blockSize, ui32 sampleCount, TVector<TIndicesType>* orderPtr) {
        TRandom rng(seed);
        rng.Advance(10);
        auto& order = *orderPtr;
        order.yresize(sampleCount);
        std::iota(order.begin(), order.end(), 0);

        if (blockSize == 1) {
            ::Shuffle(order.begin(), order.begin() + sampleCount, rng);
        } else {
            const auto blocksCount = static_cast<ui32>(::NHelpers::CeilDivide(order.size(), blockSize));
            TVector<ui32> blocks;
            blocks.yresize(blocksCount);
            std::iota(blocks.begin(), blocks.end(), 0);
            ::Shuffle(blocks.begin(), blocks.end(), rng);

            ui32 cursor = 0;
            for (ui32 i = 0; i < blocksCount; ++i) {
                const ui32 blockStart = blocks[i] * blockSize;
                const ui32 blockEnd = Min<ui32>(blockStart + blockSize, order.size());
                for (ui32 j = blockStart; j < blockEnd; ++j) {
                    order[cursor++] = j;
                }
            }
        }
    }

    template <class TIndicesType>
    inline void GenerateQueryDocsOrder(ui64 seed, ui32 blockSize, TConstArrayRef<TGroupBounds> groupBounds, TVector<TIndicesType>* orderPtr) {