Class SamplerMixin

include/core/solver.h:904–1146

 */
template<class _Solver, class ..._Attributes>
class SamplerMixin {
public:
    typedef _Solver Solver;
    typedef typename Solver::Float Float;
    typedef typename Solver::Index Index;

    typedef std::tuple<_Attributes...> Attributes;
    typedef std::tuple<Index, Index, _Attributes...> EdgeSample;
    typedef typename Solver::Graph::Edge Edge;

    static const int kSampleSize = sizeof(EdgeSample) / sizeof(Index);
    static_assert(sizeof(EdgeSample) % sizeof(Index) == 0, "sizeof(EdgeSample) must be a multiplier of sizeof(Index)");

    Solver *solver;
    int device_id;
    cudaStream_t stream;
    Memory<double, int> random;
    curandGenerator_t generator;
    int num_partition, pool_size;

#define USING_SAMPLER_MIXIN(type) \
    using typename type::Solver; \
    using typename type::Float; \
    using typename type::Index; \
    using typename type::Attributes; \
    using typename type::Edge; \
    using type::solver; \
    using type::device_id; \
    using type::stream; \
    using type::random; \
    using type::generator; \
    using type::num_partition; \
    using type::pool_size

    /**
     * Construct a general edge sampler
     * @param _solver pointer to graph embedding solver
     * @param _device_id GPU id
     */
    SamplerMixin(Solver *_solver, int _device_id) :
            solver(_solver), device_id(_device_id), random(device_id) {
        CUDA_CHECK(cudaSetDevice(device_id));

        CUDA_CHECK(cudaStreamCreate(&stream));

        random.stream = stream;
        CURAND_CHECK(curandCreateGenerator(&generator, CURAND_RNG_PSEUDO_DEFAULT));
        std::uniform_int_distribution<unsigned long long> random_seed(0, ULLONG_MAX);
        CURAND_CHECK(curandSetPseudoRandomGeneratorSeed(generator, random_seed(seed)));
        CURAND_CHECK(curandSetStream(generator, stream));
    }

    /** Should return the additional attributes */
    virtual Attributes get_attributes(const Edge &edge) const = 0;

    /** Determine and allocate all resources for the sampler */
    void build() {
        CUDA_CHECK(cudaSetDevice(device_id));