 
 
 #define BSIZE 128
-#define N_STREAMS 1
+#define N_STREAMS 2
 
 namespace Clustering {
 namespace Density {

    int n_gpus;
    cudaGetDeviceCount(&n_gpus);
//TODO
    n_gpus = 1;

    if (n_gpus == 0) {
      std::cerr << "error: no CUDA-compatible GPUs found" << std::endl;

                              , std::size_t i_to
                              , int i_gpu) {
    ASSUME_ALIGNED(coords);
    unsigned int n_radii = radii.size();
    // make sure radii are in descending order
    std::sort(radii.begin(), radii.end(), std::greater<float>());
