LTX-Vid Transformer Inference Step [WIP: Do Not Merge]

src/maxdiffusion/__init__.py

@@ -374,6 +374,7 @@
   _import_structure["models.unet_2d_condition_flax"] = ["FlaxUNet2DConditionModel"]
   _import_structure["models.flux.transformers.transformer_flux_flax"] = ["FluxTransformer2DModel"]
   _import_structure["models.vae_flax"] = ["FlaxAutoencoderKL"]
+  _import_structure["models.ltx_video.transformers.transformer3d"] = ["Transformer3DModel"]
   _import_structure["pipelines"].extend(["FlaxDiffusionPipeline"])
   _import_structure["schedulers"].extend(
       [
@@ -453,6 +454,7 @@
     from .models.modeling_flax_utils import FlaxModelMixin
     from .models.unet_2d_condition_flax import FlaxUNet2DConditionModel
     from .models.flux.transformers.transformer_flux_flax import FluxTransformer2DModel
+    from .models.ltx_video.transformers.transformer3d import Transformer3DModel
     from .models.vae_flax import FlaxAutoencoderKL
     from .pipelines import FlaxDiffusionPipeline
     from .schedulers import (

src/maxdiffusion/configs/ltx_video.yml

@@ -0,0 +1,68 @@
+#  Copyright 2025 Google LLC
+
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+
+#       https://www.apache.org/licenses/LICENSE-2.0
+
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+
+#hardware
+hardware: 'tpu'
+skip_jax_distributed_system: False
+
+jax_cache_dir: ''
+weights_dtype: 'bfloat16'
+activations_dtype: 'bfloat16'
+
+
+run_name: ''
+output_dir: 'ltx-video-output'
+save_config_to_gcs: False
+
+#parallelism
+mesh_axes: ['data', 'fsdp', 'tensor']
+logical_axis_rules: [
+                      ['batch', 'data'],
+                      ['activation_heads', 'fsdp'],
+                      ['activation_batch', ['data','fsdp']],
+                      ['activation_kv', 'tensor'],
+                      ['mlp','tensor'],
+                      ['embed','fsdp'],
+                      ['heads', 'tensor'],
+                      ['norm', 'fsdp'],
+                      ['conv_batch', ['data','fsdp']],
+                      ['out_channels', 'tensor'],
+                      ['conv_out', 'fsdp'],
+                      ['conv_in', 'fsdp']
+                    ]
+data_sharding: [['data', 'fsdp', 'tensor']]
+dcn_data_parallelism: 1  # recommended DCN axis to be auto-sharded
+dcn_fsdp_parallelism: -1
+dcn_tensor_parallelism: 1
+ici_data_parallelism: 1
+ici_fsdp_parallelism: -1  # recommended ICI axis to be auto-sharded
+ici_tensor_parallelism: 1
+
+
+
+
+learning_rate_schedule_steps: -1
+max_train_steps: 500 #TODO: change this
+pretrained_model_name_or_path: ''
+unet_checkpoint: ''
+dataset_name: 'diffusers/pokemon-gpt4-captions'
+train_split: 'train'
+dataset_type: 'tf'
+cache_latents_text_encoder_outputs: True
+per_device_batch_size: 1
+compile_topology_num_slices: -1 
+quantization_local_shard_count: -1
+jit_initializers: True 
+enable_single_replica_ckpt_restoring: False

src/maxdiffusion/generate_ltx_video.py

@@ -0,0 +1,186 @@
+from absl import app
+from typing import Sequence
+import jax
+import json
+from flax.linen import partitioning as nn_partitioning
+from maxdiffusion.models.ltx_video.transformers.transformer3d import Transformer3DModel
+import os
+import functools
+import jax.numpy as jnp
+from maxdiffusion import pyconfig
+from maxdiffusion.max_utils import (
+    create_device_mesh,
+    setup_initial_state,
+    get_memory_allocations,
+)
+from jax.sharding import Mesh, PartitionSpec as P
+import orbax.checkpoint as ocp
+
+
+def validate_transformer_inputs(
+    prompt_embeds, fractional_coords, latents, noise_cond, segment_ids, encoder_attention_segment_ids
+):
+  print("prompts_embeds.shape: ", prompt_embeds.shape, prompt_embeds.dtype)
+  print("fractional_coords.shape: ", fractional_coords.shape, fractional_coords.dtype)
+  print("latents.shape: ", latents.shape, latents.dtype)
+  print("noise_cond.shape: ", noise_cond.shape, noise_cond.dtype)
+  print("noise_cond.shape: ", noise_cond.shape, noise_cond.dtype)
+  print("segment_ids.shape: ", segment_ids.shape, segment_ids.dtype)
+  print("encoder_attention_segment_ids.shape: ", encoder_attention_segment_ids.shape, encoder_attention_segment_ids.dtype)
+
+
+def loop_body(step, args, transformer, fractional_cords, prompt_embeds, segment_ids, encoder_attention_segment_ids):
+  latents, state, noise_cond = args
+  noise_pred = transformer.apply(
+      {"params": state.params},
+      hidden_states=latents,
+      indices_grid=fractional_cords,
+      encoder_hidden_states=prompt_embeds,
+      timestep=noise_cond,
+      segment_ids=segment_ids,
+      encoder_attention_segment_ids=encoder_attention_segment_ids,
+  )
+  return noise_pred, state, noise_cond
+
+
+def run_inference(
+    states,
+    transformer,
+    config,
+    mesh,
+    latents,
+    fractional_cords,
+    prompt_embeds,
+    timestep,
+    segment_ids,
+    encoder_attention_segment_ids,
+):
+  transformer_state = states["transformer"]
+  loop_body_p = functools.partial(
+      loop_body,
+      transformer=transformer,
+      fractional_cords=fractional_cords,
+      prompt_embeds=prompt_embeds,
+      segment_ids=segment_ids,
+      encoder_attention_segment_ids=encoder_attention_segment_ids,
+  )
+
+  with mesh, nn_partitioning.axis_rules(config.logical_axis_rules):
+    noise_pred, transformer_state, _ = jax.lax.fori_loop(0, 1, loop_body_p, (latents, transformer_state, timestep))
+  return noise_pred
+
+
+def run(config):
+  key = jax.random.PRNGKey(42)
+
+  devices_array = create_device_mesh(config)
+  mesh = Mesh(devices_array, config.mesh_axes)
+
+  base_dir = os.path.dirname(__file__)
+
+  ##load in model config
+  config_path = os.path.join(base_dir, "models/ltx_video/xora_v1.2-13B-balanced-128.json")
+  with open(config_path, "r") as f:
+    model_config = json.load(f)
+  relative_ckpt_path = model_config["ckpt_path"]
+
+  ignored_keys = [
+      "_class_name",
+      "_diffusers_version",
+      "_name_or_path",
+      "causal_temporal_positioning",
+      "in_channels",
+      "ckpt_path",
+  ]
+  in_channels = model_config["in_channels"]
+  for name in ignored_keys:
+    if name in model_config:
+      del model_config[name]
+
+  transformer = Transformer3DModel(
+      **model_config, dtype=jnp.float32, gradient_checkpointing="matmul_without_batch", sharding_mesh=mesh
+  )
+  transformer_param_shapes = transformer.init_weights(in_channels, key, model_config["caption_channels"], eval_only=True)  # noqa F841
+  weights_init_fn = functools.partial(
+      transformer.init_weights, in_channels, key, model_config["caption_channels"], eval_only=True
+  )
+
+  absolute_ckpt_path = os.path.abspath(relative_ckpt_path)
+
+  checkpoint_manager = ocp.CheckpointManager(absolute_ckpt_path)
+  transformer_state, transformer_state_shardings = setup_initial_state(
+      model=transformer,
+      tx=None,
+      config=config,
+      mesh=mesh,
+      weights_init_fn=weights_init_fn,
+      checkpoint_manager=checkpoint_manager,
+      checkpoint_item=" ",
+      model_params=None,
+      training=False,
+  )
+
+  transformer_state = jax.device_put(transformer_state, transformer_state_shardings)
+  get_memory_allocations()
+
+  states = {}
+  state_shardings = {}
+
+  state_shardings["transformer"] = transformer_state_shardings
+  states["transformer"] = transformer_state
+
+  # create dummy inputs:
+  example_inputs = {}
+  batch_size, num_tokens = 4, 256
+  input_shapes = {
+      "latents": (batch_size, num_tokens, in_channels),
+      "fractional_coords": (batch_size, 3, num_tokens),
+      "prompt_embeds": (batch_size, 128, model_config["caption_channels"]),
+      "timestep": (batch_size, 256),
+      "segment_ids": (batch_size, 256),
+      "encoder_attention_segment_ids": (batch_size, 128),
+  }
+  for name, shape in input_shapes.items():
+    example_inputs[name] = jnp.ones(
+        shape, dtype=jnp.float32 if name not in ["attention_mask", "encoder_attention_mask"] else jnp.bool
+    )
+
+  data_sharding = jax.sharding.NamedSharding(mesh, P(*config.data_sharding))
+  latents = jax.device_put(example_inputs["latents"], data_sharding)
+  prompt_embeds = jax.device_put(example_inputs["prompt_embeds"], data_sharding)
+  fractional_coords = jax.device_put(example_inputs["fractional_coords"], data_sharding)
+  noise_cond = jax.device_put(example_inputs["timestep"], data_sharding)
+  segment_ids = jax.device_put(example_inputs["segment_ids"], data_sharding)
+  encoder_attention_segment_ids = jax.device_put(example_inputs["encoder_attention_segment_ids"], data_sharding)
+
+  validate_transformer_inputs(
+      prompt_embeds, fractional_coords, latents, noise_cond, segment_ids, encoder_attention_segment_ids
+  )
+  p_run_inference = jax.jit(
+      functools.partial(
+          run_inference,
+          transformer=transformer,
+          config=config,
+          mesh=mesh,
+          latents=latents,
+          fractional_cords=fractional_coords,
+          prompt_embeds=prompt_embeds,
+          timestep=noise_cond,
+          segment_ids=segment_ids,
+          encoder_attention_segment_ids=encoder_attention_segment_ids,
+      ),
+      in_shardings=(state_shardings,),
+      out_shardings=None,
+  )
+
+  noise_pred = p_run_inference(states).block_until_ready()
+  print(noise_pred)  # (4, 256, 128)
+
+
+def main(argv: Sequence[str]) -> None:
+  pyconfig.initialize(argv)
+  run(pyconfig.config)
+
+
+if __name__ == "__main__":
+  app.run(main)

src/maxdiffusion/max_utils.py

@@ -609,4 +609,4 @@ def maybe_initialize_jax_distributed_system(raw_keys):
     initialize_jax_for_gpu()
     max_logging.log("Jax distributed system initialized on GPU!")
   else:
-    jax.distributed.initialize()
+    jax.distributed.initialize()

src/maxdiffusion/models/__init__.py

@@ -13,9 +13,7 @@
 # limitations under the License.
 
 from typing import TYPE_CHECKING
-
-from ..utils import DIFFUSERS_SLOW_IMPORT, _LazyModule, is_flax_available, is_torch_available
-
+from maxdiffusion.utils import DIFFUSERS_SLOW_IMPORT, _LazyModule, is_flax_available, is_torch_available
 
 _import_structure = {}
 
@@ -32,6 +30,7 @@
   from .vae_flax import FlaxAutoencoderKL
   from .lora import *
   from .flux.transformers.transformer_flux_flax import FluxTransformer2DModel
+  from .ltx_video.transformers.transformer3d import Transformer3DModel
 
 else:
   import sys

src/maxdiffusion/models/ltx_video/gradient_checkpoint.py

@@ -0,0 +1,70 @@
+from enum import Enum, auto
+from typing import Optional
+
+import jax
+from flax import linen as nn
+
+SKIP_GRADIENT_CHECKPOINT_KEY = "skip"
+
+
+class GradientCheckpointType(Enum):
+  """
+  Defines the type of the gradient checkpoint we will have
+
+  NONE - means no gradient checkpoint
+  FULL - means full gradient checkpoint, wherever possible (minimum memory usage)
+  MATMUL_WITHOUT_BATCH - means gradient checkpoint for every linear/matmul operation,
+                          except for ones that involve batch dimension - that means that all attention and projection
+                          layers will have gradient checkpoint, but not the backward with respect to the parameters
+  """
+
+  NONE = auto()
+  FULL = auto()
+  MATMUL_WITHOUT_BATCH = auto()
+
+  @classmethod
+  def from_str(cls, s: Optional[str] = None) -> "GradientCheckpointType":
+    """
+    Constructs the gradient checkpoint type from a string
+
+    Args:
+        s (Optional[str], optional): The name of the gradient checkpointing policy. Defaults to None.
+
+    Returns:
+        GradientCheckpointType: The policy that corresponds to the string
+    """
+    if s is None:
+      s = "none"
+    return GradientCheckpointType[s.upper()]
+
+  def to_jax_policy(self):
+    """
+    Converts the gradient checkpoint type to a jax policy
+    """
+    match self:
+      case GradientCheckpointType.NONE:
+        return SKIP_GRADIENT_CHECKPOINT_KEY
+      case GradientCheckpointType.FULL:
+        return None
+      case GradientCheckpointType.MATMUL_WITHOUT_BATCH:
+        return jax.checkpoint_policies.checkpoint_dots_with_no_batch_dims
+
+  def apply(self, module: nn.Module) -> nn.Module:
+    """
+    Applies a gradient checkpoint policy to a module
+    if no policy is needed, it will return the module as is
+
+    Args:
+        module (nn.Module): the module to apply the policy to
+
+    Returns:
+        nn.Module: the module with the policy applied
+    """
+    policy = self.to_jax_policy()
+    if policy == SKIP_GRADIENT_CHECKPOINT_KEY:
+      return module
+    return nn.remat(  # pylint: disable=invalid-name
+        module,
+        prevent_cse=False,
+        policy=policy,
+    )