                        cudaMemcpyHostToDevice));
   gpuErrchk(cudaMemcpy(vars->gpu_z, coords.z, atomNumber * sizeof(double),
                        cudaMemcpyHostToDevice));
-  checkLastErrorCUDA(__FILE__, __LINE__);
 
   // Run the kernel...
   threadsPerBlock = 256;

                          cudaMemcpyDeviceToHost));
  REn = cpu_final_REn;
  LJEn = cpu_final_LJEn;

  cudaDeviceSynchronize();

  cudaFree(gpu_pair1);
  cudaFree(gpu_pair2);

      vars->gpu_lambdaCoulomb,
      vars->gpu_isFraction,
      box);
  cudaDeviceSynchronize();
  checkLastErrorCUDA(__FILE__, __LINE__);

  // ReduceSum
