code: def test_llff(self):
      if inside_re_worker:
          return
      expand_args_fields(LlffDatasetMapProvider)
  
      provider = LlffDatasetMapProvider(
          base_dir="manifold://co3d/tree/nerf_data/nerf_llff_data/fern",
          object_name="fern",
          downscale_factor=8,
      )
      dataset_map = provider.get_dataset_map()
      known_matrix = torch.zeros(1, 4, 4)
      known_matrix[0, 0, 0] = 2.1564
      known_matrix[0, 1, 1] = 2.1564
      known_matrix[0, 2, 3] = 1
      known_matrix[0, 3, 2] = 1
  
      for name, length, frame_type in [
          ("train", 17, "known"),
          ("test", 3, "unseen"),
          ("val", 3, "unseen"),
      ]:
          dataset = getattr(dataset_map, name)
          self.assertEqual(len(dataset), length)
          # try getting a value
          value = dataset[0]
          self.assertIsInstance(value, FrameData)
          self.assertEqual(value.frame_type, frame_type)
          self.assertEqual(value.image_rgb.shape, (3, 378, 504))
          self.assertIsInstance(value.camera, PerspectiveCameras)
          self.assertEqual(len(value.camera), 1)
          self.assertIsNone(value.camera.K)
          matrix = value.camera.get_projection_transform().get_matrix()
          self.assertClose(matrix, known_matrix, atol=1e-4)
  
      self.assertEqual(len(dataset_map.test.get_eval_batches()), 3)
      for batch in dataset_map.test.get_eval_batches():
          self.assertEqual(len(batch), 1)
          self.assertEqual(
              dataset_map.test[batch[0]].frame_type, "unseen"
          )
  
file_path: pytorch3d/tests/implicitron/test_data_llff.py
imports: import os
  import unittest
  import torch
  from pytorch3d.implicitron.dataset.blender_dataset_map_provider import BlenderDatasetMapProvider
  from pytorch3d.implicitron.dataset.data_source import ImplicitronDataSource
  from pytorch3d.implicitron.dataset.dataset_base import FrameData
  from pytorch3d.implicitron.dataset.llff_dataset_map_provider import LlffDatasetMapProvider
  from pytorch3d.implicitron.tools.config import expand_args_fields, get_default_args
  from pytorch3d.renderer import PerspectiveCameras
  from tests.common_testing import TestCaseMixin
label_desc: Use image node_id 2 for calling the TestDataLlff obj's underlying member method code with example usage: obj.test_llff() without return types