code: def test_single_ray(self, device, dtype):
      camera: PinholeCamera = create_one_camera(5, 9, device, dtype)
      img: list[Tensor] = create_red_images_for_cameras(camera, device)
  
      nerf_obj = NerfSolver(device=device, dtype=dtype)
      nerf_obj.setup_solver(camera, 1.0, 3.0, True, img, 1, 2, 10)
      nerf_obj.run(num_epochs=20)
  
file_path: kornia/test/nerf/test_nerf_solver.py
imports: import pytest
  import torch
  from kornia.core import Tensor
  from kornia.geometry.camera import PinholeCamera
  from kornia.nerf.nerf_model import NerfModelRenderer
  from kornia.nerf.nerf_solver import NerfSolver
  from kornia.testing import assert_close
  from test.nerf.test_data_utils import create_random_images_for_cameras, create_red_images_for_cameras
  from test.nerf.test_rays import create_four_cameras, create_one_camera
label_desc: Use image node_id 3 for calling the TestNerfSolver obj's underlying member method code with example usage: obj.test_single_ray(device, dtype) without return types