     CudaCheckError();
     #endif
  
-    // Step 7: Calculate the next time step
+    // Step 4: Calculate the next time step
     #ifndef GRAVITY_COUPLE_CPU //If gravity is coupled on the CPU, dt is computed on the CPU after hydro update
     Calc_dt_3D<<<dim1dGrid,dim1dBlock>>>(dev_conserved, nx_s, ny_s, nz_s, n_ghost, dx, dy, dz, dev_dti_array, gama);
     CudaCheckError();


    // allocate memory on the GPU
    CudaSafeCall( cudaMalloc((void**)&dev_conserved, n_fields*BLOCK_VOL*sizeof(Real)) );
    CudaSafeCall( cudaMalloc((void**)&dev_conserved_half, n_fields*BLOCK_VOL*sizeof(Real)) );
    CudaSafeCall( cudaMalloc((void**)&Q_Lx,  n_fields*BLOCK_VOL*sizeof(Real)) );
    CudaSafeCall( cudaMalloc((void**)&Q_Rx,  n_fields*BLOCK_VOL*sizeof(Real)) );
    CudaSafeCall( cudaMalloc((void**)&Q_Ly,  n_fields*BLOCK_VOL*sizeof(Real)) );

  
  // free the GPU memory
  cudaFree(dev_conserved);
  // cudaFree(dev_conserved_half);
  cudaFree(Q_Lx);
  cudaFree(Q_Rx);
  cudaFree(Q_Ly);
