     BLOCK_VOL = nx_s*ny_s*nz_s;
     // dimensions for the 1D GPU grid
     ngrid = (BLOCK_VOL + TPB - 1) / TPB;
+    #ifndef DYNAMIC_GPU_ALLOC
     block_size = true;
+    #endif
   }
   // set values for GPU kernels
   // number of blocks per 1D grid  

  #endif


  #ifdef SINGLE_ALLOC_GPU
  chprintf( " VL_3D: Memory freed successfully \n");
  #endif
}

    CudaSafeCall( cudaMalloc((void**)&dev_dt_array, ngrid*sizeof(Real)) );
    #endif 
    
    #ifndef DYNAMIC_GPU_ALLOC 
    chprintf( " VL_3D: Allocating memory \n");
    chprintf ( "  N memory blocks gpu: %d\n", block_tot );
    // If memory is single allocated: memory_allocated becomes true and succesive timesteps won't allocate memory.
