Merge pull request #240 from Project-MONAI/217_set_default_inference_timesteps

Initialise inference_timesteps to train_timesteps

Author: ericspod

generative/networks/schedulers/ddim.py

@@ -103,13 +103,15 @@ def __init__(
         # standard deviation of the initial noise distribution
         self.init_noise_sigma = 1.0
 
-        # setable values
-        self.num_inference_steps = None
+
         self.timesteps = torch.from_numpy(np.arange(0, num_train_timesteps)[::-1].astype(np.int64))
 
         self.clip_sample = clip_sample
         self.steps_offset = steps_offset
 
+        # default the number of inference timesteps to the number of train steps
+        self.set_timesteps(num_train_timesteps)
+
     def set_timesteps(self, num_inference_steps: int, device: str | torch.device | None = None) -> None:
         """
         Sets the discrete timesteps used for the diffusion chain. Supporting function to be run before inference.

generative/networks/schedulers/pndm.py

@@ -117,13 +117,11 @@ def __init__(
         self.cur_sample = None
         self.ets = []
 
-        # settable values
-        self.num_inference_steps = None
+
         self._timesteps = np.arange(0, num_train_timesteps)[::-1].copy()
-        self.prk_timesteps = torch.Tensor([])
-        self.plms_timesteps = torch.Tensor([])
-        self.timesteps = torch.Tensor([])
 
+        # default the number of inference timesteps to the number of train steps
+        self.set_timesteps(num_train_timesteps)
     def set_timesteps(self, num_inference_steps: int, device: str | torch.device | None = None) -> None:
         """
         Sets the discrete timesteps used for the diffusion chain. Supporting function to be run before inference.

tests/test_scheduler_pndm.py

@@ -39,13 +39,6 @@ def test_add_noise_2d_shape(self, input_param, input_shape, expected_shape):
         noisy = scheduler.add_noise(original_samples=original_sample, noise=noise, timesteps=timesteps)
         self.assertEqual(noisy.shape, expected_shape)
 
-    @parameterized.expand(TEST_CASES)
-    def test_error_if_timesteps_not_set(self, input_param, input_shape, expected_shape):
-        scheduler = PNDMScheduler(**input_param)
-        with self.assertRaises(ValueError):
-            model_output = torch.randn(input_shape)
-            sample = torch.randn(input_shape)
-            scheduler.step(model_output=model_output, timestep=500, sample=sample)
 
     @parameterized.expand(TEST_CASES)
     def test_step_shape(self, input_param, input_shape, expected_shape):