lerobot/lerobot/common/policies/pi0fast/modeling_pi0fast.py

1077 lines
44 KiB
Python
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#!/usr/bin/env python
# Copyright 2025 Physical Intelligence and The HuggingFace Inc. team. All rights reserved.
#
# 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
#
# http://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.
"""
π0+FAST: Efficient Action Tokenization for Vision-Language-Action Models
[Paper](https://arxiv.org/abs/2501.09747)
[Jax code](https://github.com/Physical-Intelligence/openpi)
Designed by Physical Intelligence. Ported from Jax by Hugging Face.
Example of finetuning the pi0+FAST pretrained model (`pi0_fast_base` in `openpi`):
```bash
python lerobot/scripts/train.py \
--policy.path=lerobot/pi0fast \
--dataset.repo_id=danaaubakirova/koch_test
```
Example of finetuning the pi0+FAST neural network with PaliGemma and expert Gemma
pretrained with VLM default parameters before pi0+FAST finetuning:
```bash
python lerobot/scripts/train.py \
--policy.type=pi0fast \
--dataset.repo_id=danaaubakirova/koch_test
```
Example of using the pi0 pretrained model outside LeRobot training framework:
```python
policy = PI0FASTPolicy.from_pretrained("lerobot/pi0fast")
```
"""
from collections import deque
from functools import partial
import numpy as np
import torch
import torch.nn.functional as F # noqa: N812
# from peft import LoraConfig, TaskType, get_peft_model
from PIL import Image
from scipy.fft import idct
from torch import Tensor, nn
from transformers import AutoProcessor, AutoTokenizer, PaliGemmaForConditionalGeneration
from transformers.cache_utils import HybridCache, StaticCache
from transformers.models.auto import CONFIG_MAPPING
from lerobot.common.constants import ACTION, OBS_ROBOT
from lerobot.common.policies.normalize import Normalize, Unnormalize
from lerobot.common.policies.pi0fast.configuration_pi0fast import PI0FASTConfig
from lerobot.common.policies.pretrained import PreTrainedPolicy
from lerobot.common.constants import ACTION, OBS_IMAGE, OBS_IMAGE_2, OBS_IMAGE_3, OBS_ROBOT
IMAGES_ORDER = {
OBS_IMAGE: 0,
OBS_IMAGE_2: 1,
OBS_IMAGE_3: 2,
}
PRECISION = {
"float16": torch.float16,
"float32": torch.float32,
"bfloat16": torch.bfloat16,
}
def display(tensor: torch.Tensor):
if tensor.dtype == torch.bool:
tensor = tensor.float()
print(f"Shape: {tensor.shape}")
print(f"Mean: {tensor.mean().item()}")
print(f"Std: {tensor.std().item()}")
print(f"Min: {tensor.min().item()}")
print(f"Max: {tensor.max().item()}")
def normalize(x, min_val, max_val):
return (x - min_val) / (max_val - min_val)
def unnormalize(x, min_val, max_val):
return x * (max_val - min_val) + min_val
def safe_arcsin(value):
# This ensures that the input stays within
# [1,1] to avoid invalid values for arcsin
return torch.arcsin(torch.clamp(value, -1.0, 1.0))
def aloha_gripper_to_angular(value):
# Aloha transforms the gripper positions into a linear space. The following code
# reverses this transformation to be consistent with pi0 which is pretrained in
# angular space.
#
# These values are coming from the Aloha code:
# PUPPET_GRIPPER_POSITION_OPEN, PUPPET_GRIPPER_POSITION_CLOSED
value = unnormalize(value, min_val=0.01844, max_val=0.05800)
# This is the inverse of the angular to linear transformation inside the Interbotix code.
def linear_to_radian(linear_position, arm_length, horn_radius):
value = (horn_radius**2 + linear_position**2 - arm_length**2) / (2 * horn_radius * linear_position)
return safe_arcsin(value)
# The constants are taken from the Interbotix code.
value = linear_to_radian(value, arm_length=0.036, horn_radius=0.022)
# Normalize to [0, 1].
# The values 0.4 and 1.5 were measured on an actual Trossen robot.
return normalize(value, min_val=0.4, max_val=1.5)
def aloha_gripper_from_angular(value):
# Convert from the gripper position used by pi0 to the gripper position that is used by Aloha.
# Note that the units are still angular but the range is different.
# The values 0.4 and 1.5 were measured on an actual Trossen robot.
value = unnormalize(value, min_val=0.4, max_val=1.5)
# These values are coming from the Aloha code:
# PUPPET_GRIPPER_JOINT_OPEN, PUPPET_GRIPPER_JOINT_CLOSE
return normalize(value, min_val=-0.6213, max_val=1.4910)
def aloha_gripper_from_angular_inv(value):
# Directly inverts the gripper_from_angular function.
value = unnormalize(value, min_val=-0.6213, max_val=1.4910)
return normalize(value, min_val=0.4, max_val=1.5)
class PI0FASTPolicy(PreTrainedPolicy):
"""Wrapper class around PI0FAST tokenizer and model to train and run inference within LeRobot."""
config_class = PI0FASTConfig
name = "pi0fast"
def __init__(
self,
config: PI0FASTConfig,
dataset_stats: dict[str, dict[str, Tensor]] | None = None,
):
"""
Args:
config: Policy configuration class instance or None, in which case the default instantiation of
the configuration class is used.
dataset_stats: Dataset statistics to be used for normalization. If not passed here, it is expected
that they will be passed with a call to `load_state_dict` before the policy is used.
"""
super().__init__(config)
config.validate_features()
self.config = config
self.normalize_inputs = Normalize(config.input_features, config.normalization_mapping, dataset_stats)
self.normalize_targets = Normalize(
config.output_features, config.normalization_mapping, dataset_stats
)
self.unnormalize_outputs = Unnormalize(
config.output_features, config.normalization_mapping, dataset_stats
)
self.language_tokenizer = AutoProcessor.from_pretrained("google/paligemma-3b-pt-224")
self.model = PI0FAST(config)
self.adapt_to_pi_aloha = True #self.config.adapt_to_pi_aloha # FIXME(mshukor): debug
self.reset()
def reset(self):
"""This should be called whenever the environment is reset."""
self._action_queue = deque([], maxlen=self.config.n_action_steps)
def get_optim_params(self) -> dict:
return self.parameters()
def _pi_aloha_decode_state(self, state):
# Flip the joints.
for motor_idx in [1, 2, 8, 9]:
state[:, motor_idx] *= -1
# Reverse the gripper transformation that is being applied by the Aloha runtime.
for motor_idx in [6, 13]:
state[:, motor_idx] = aloha_gripper_to_angular(state[:, motor_idx])
return state
def _pi_aloha_encode_actions(self, actions):
# Flip the joints.
for motor_idx in [1, 2, 8, 9]:
actions[:, :, motor_idx] *= -1
# Reverse the gripper transformation that is being applied by the Aloha runtime.
for motor_idx in [6, 13]:
actions[:, :, motor_idx] = aloha_gripper_from_angular(actions[:, :, motor_idx])
return actions
def _pi_aloha_encode_actions_inv(self, actions):
# Flip the joints again.
for motor_idx in [1, 2, 8, 9]:
actions[:, :, motor_idx] *= -1
# Reverse the gripper transformation that is being applied by the Aloha runtime.
for motor_idx in [6, 13]:
actions[:, :, motor_idx] = aloha_gripper_from_angular_inv(actions[:, :, motor_idx])
return actions
@torch.no_grad
def select_action(self, batch: dict[str, Tensor]) -> Tensor:
"""Select a single action given environment observations.
This method wraps `select_actions` in order to return one action at a time for execution in the
environment. It works by managing the actions in a queue and only calling `select_actions` when the
queue is empty.
"""
self.eval()
if self.adapt_to_pi_aloha:
batch[OBS_ROBOT] = self._pi_aloha_decode_state(batch[OBS_ROBOT])
batch = self.normalize_inputs(batch)
# Action queue logic for n_action_steps > 1. When the action_queue is depleted, populate it by
# querying the policy.
if len(self._action_queue) == 0:
actions = self.model.generate_actions(batch)
actions = actions[:, : self.config.n_action_steps]
original_action_dim = self.config.action_feature.shape[
0
] # self.config.max_action_dim # self.config.action_feature.shape[0]
actions = actions[:, :, :original_action_dim]
actions = self.unnormalize_outputs({"action": actions})["action"]
if self.adapt_to_pi_aloha:
actions = self._pi_aloha_encode_actions(actions)
# `self.model.forward` returns a (batch_size, n_action_steps, action_dim) tensor, but the queue
# effectively has shape (n_action_steps, batch_size, *), hence the transpose.
self._action_queue.extend(actions.transpose(0, 1))
return self._action_queue.popleft()
def forward(self, batch: dict[str, Tensor]) -> dict[str, Tensor]:
if self.adapt_to_pi_aloha:
batch[OBS_ROBOT] = self._pi_aloha_decode_state(batch[OBS_ROBOT])
batch[ACTION] = self._pi_aloha_encode_actions_inv(batch[ACTION])
batch = self.normalize_inputs(batch)
batch = self.normalize_targets(batch)
loss_dict = self.model.forward(batch)
return loss_dict["loss"], loss_dict
def block_causal_update_causal_mask(
# self,
attention_mask,
token_type_ids=None,
past_key_values=None,
cache_position=None,
input_tensor=None,
# is_training: bool = None,
attn_implementation: str = "eager",
dtype: torch.dtype = "float32",
):
if attn_implementation == "flash_attention_2":
if attention_mask is not None and 0.0 in attention_mask:
return attention_mask
return None
# dtype = self.pi0_paligemma.dtype
# is_training = is_training if is_training is not None else self.training
using_static_cache = isinstance(past_key_values, StaticCache)
min_dtype = torch.finfo(dtype).min
if input_tensor is None:
input_tensor = attention_mask
inputs_lead_dim, sequence_length = input_tensor.shape[:2]
if using_static_cache or isinstance(past_key_values, HybridCache):
target_length = past_key_values.get_max_cache_shape()
else:
target_length = (
attention_mask.shape[-1]
if isinstance(attention_mask, torch.Tensor)
else cache_position[0] + sequence_length + 1
)
# Handle precomputed attention masks
if attention_mask is not None and attention_mask.dim() == 4:
return attention_mask
# Causal mask initialization
causal_mask = torch.full(
(sequence_length, target_length), fill_value=min_dtype, dtype=dtype, device=cache_position.device
)
# Standard causal masking (triu ensures tokens can only attend to past)
if sequence_length != 1:
causal_mask = torch.triu(causal_mask, diagonal=1)
# Apply block causal mask
if token_type_ids is not None:
token_type_ids = token_type_ids.to(causal_mask.device).bool()
cumsum = torch.cumsum(token_type_ids, dim=1)
block_causal_mask = cumsum[:, None, :] <= cumsum[:, :, None]
# Combine causal_mask with block-wise attention mask
causal_mask = torch.where(block_causal_mask, 0.0, causal_mask)
causal_mask = causal_mask[:, None, :, :]
else:
# Apply past cache position constraint
causal_mask *= torch.arange(target_length, device=cache_position.device) > cache_position.reshape(
-1, 1
)
causal_mask = causal_mask[None, None, :, :].expand(inputs_lead_dim, 1, -1, -1)
else:
# Apply past cache position constraint
causal_mask *= torch.arange(target_length, device=cache_position.device) > cache_position.reshape(
-1, 1
)
causal_mask = causal_mask[None, None, :, :].expand(inputs_lead_dim, 1, -1, -1)
if attention_mask is not None:
causal_mask = causal_mask.clone() # Copy to contiguous memory for in-place edits
mask_length = attention_mask.shape[-1]
# Apply padding mask
padding_mask = causal_mask[:, :, :, :mask_length] + attention_mask[:, None, None, :].to(
causal_mask.device
)
padding_mask = padding_mask == 0
causal_mask[:, :, :, :mask_length] = causal_mask[:, :, :, :mask_length].masked_fill(
padding_mask, min_dtype
)
return causal_mask
def prepare_inputs_for_generation(
# self,
input_ids,
past_key_values=None,
inputs_embeds=None,
cache_position=None,
position_ids=None,
pixel_values=None,
attention_mask=None,
token_type_ids=None,
use_cache=True,
num_logits_to_keep=None,
labels=None,
self=None,
**kwargs,
):
# create block causal attention
if cache_position[0] > 0 and input_ids.shape[1] > 0:
input_tensor = input_ids[:, -1:]
new_positions = (
torch.ones(
(position_ids.shape[0], input_ids.shape[1]),
dtype=position_ids.dtype,
device=position_ids.device,
).cumsum(-1)
+ position_ids[:, -1:]
)
position_ids = torch.cat([position_ids, new_positions], dim=-1)
else:
input_tensor = inputs_embeds
attention_mask = block_causal_update_causal_mask(
attention_mask=attention_mask,
past_key_values=past_key_values,
cache_position=cache_position,
input_tensor=input_tensor,
token_type_ids=token_type_ids,
dtype=self.dtype,
attn_implementation=self.config.text_config._attn_implementation,
)
# Overwritten -- custom `position_ids` and `pixel_values` handling
model_inputs = self.language_model.prepare_inputs_for_generation(
input_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
attention_mask=attention_mask,
position_ids=position_ids,
cache_position=cache_position,
use_cache=use_cache,
num_logits_to_keep=num_logits_to_keep,
token_type_ids=token_type_ids,
**kwargs,
)
# position_ids in Paligemma are 1-indexed
if model_inputs.get("position_ids") is not None:
model_inputs["position_ids"] += 1
# If we're in cached decoding stage, pixel values should be None because input ids do not contain special image token anymore
# Otherwise we need pixel values to be passed to model. NOTE: use_cache=False needs pixel_values always
if cache_position[0] == 0:
model_inputs["pixel_values"] = pixel_values
is_training = token_type_ids is not None and labels is not None
if cache_position[0] == 0 and isinstance(past_key_values, HybridCache):
input_tensor = inputs_embeds if inputs_embeds is not None else input_ids
causal_mask = self._update_causal_mask(
attention_mask, token_type_ids, past_key_values, cache_position, input_tensor, is_training
)
model_inputs["attention_mask"] = causal_mask
return model_inputs
class PI0FAST(nn.Module):
def __init__(self, config: PI0FASTConfig):
super().__init__()
self.config = config
# TODO: move tokenizers in Policy
fast_tokenizer_path = "physical-intelligence/fast"
pi0_paligemma_path = "google/paligemma-3b-pt-224"
self.paligemma_tokenizer = AutoTokenizer.from_pretrained(pi0_paligemma_path)
self.processor = AutoProcessor.from_pretrained(pi0_paligemma_path)
self.fast_tokenizer = AutoProcessor.from_pretrained(fast_tokenizer_path, trust_remote_code=True)
self.fast_skip_tokens = self.config.fast_skip_tokens
self.max_input_seq_len = self.config.max_input_seq_len
self.action_horizon = self.config.chunk_size
self.action_dim = self.config.action_feature.shape[0] #self.config.max_action_dim # self.config.action_feature.shape[0]
precision = config.precision
torch_precision = PRECISION.get(precision, torch.float32)
self.pad_token_id = (
self.paligemma_tokenizer.pad_token_id
if hasattr(self.paligemma_tokenizer, "pad_token_id")
else self.paligemma_tokenizer.eos_token_id
)
paligemma_config = CONFIG_MAPPING["paligemma"](
transformers_version="4.48.1",
_vocab_size=257152,
bos_token_id=2,
eos_token_id=1,
hidden_size=2048,
image_token_index=257152,
model_type="paligemma",
pad_token_id=0,
projection_dim=2048,
text_config={
"hidden_activation": "gelu_pytorch_tanh",
"hidden_size": 2048,
"intermediate_size": 16384,
"model_type": "gemma",
"num_attention_heads": 8,
"num_hidden_layers": 18,
"num_image_tokens": 256,
"num_key_value_heads": 1,
"torch_dtype": precision,
"vocab_size": 257152,
"_attn_implementation": "eager",
},
vision_config={
"hidden_size": 1152,
"intermediate_size": 4304,
"model_type": "siglip_vision_model",
"num_attention_heads": 16,
"num_hidden_layers": 27,
"num_image_tokens": 256,
"patch_size": 14,
"projection_dim": 2048,
"projector_hidden_act": "gelu_pytorch_tanh",
"torch_dtype": precision,
"vision_use_head": False,
},
)
if config.load_paligemma_weights:
print("Loading google/paligemma-3b-pt-224 weights ...")
self.pi0_paligemma = PaliGemmaForConditionalGeneration.from_pretrained(
"google/paligemma-3b-pt-224",
device_map="cuda",
torch_dtype=precision,
low_cpu_mem_usage=True,
attn_implementation="eager",
)
else:
self.pi0_paligemma = PaliGemmaForConditionalGeneration(config=paligemma_config)
self.pi0_paligemma.prepare_inputs_for_generation = partial(
prepare_inputs_for_generation, self=self.pi0_paligemma
)
# self.pi0_paligemma = self.configure_peft(pi0_paligemma)
# change important stuff in bf16
params_to_change_dtype = [
"language_model",
"vision_tower",
"multi_modal",
]
print(f"Cast model params to {precision}")
for name, param in self.pi0_paligemma.named_parameters():
if any(selector in name for selector in params_to_change_dtype):
param.data = param.data.to(dtype=torch_precision)
self.set_requires_grad()
self.ignore_index = self.pi0_paligemma.config.ignore_index
self.padding_side = self.config.padding_side
def set_requires_grad(self):
if self.config.freeze_vision_encoder:
self.pi0_paligemma.vision_tower.eval()
for params in self.pi0_paligemma.vision_tower.parameters():
params.requires_grad = False
# To avoid unused params issue with distributed training
if self.config.freeze_lm_head:
for name, params in self.pi0_paligemma.named_parameters():
if any([k in name for k in ["embed_tokens"]]): # lm heads and embedding layer are tied
params.requires_grad = False
# def configure_peft(self, model):
# self.peft_method = self.config.peft_method
# if "lora" in self.peft_method:
# peft_config = self.config.peft_config
# target_modules = peft_config.target_modules
# if not isinstance(target_modules, list):
# target_modules = target_modules.split(",")
# lora_config = LoraConfig(
# task_type=TaskType.CAUSAL_LM, # Based on the task type (e.g., language modeling, etc.)
# r=peft_config.r, # The rank of the low-rank adaptation
# lora_alpha=peft_config.lora_alpha, # Scaling factor
# lora_dropout=peft_config.lora_dropout, # Dropout applied to LoRA layers
# target_modules=target_modules, # The components where LoRA is applied
# )
# self.lora_config = lora_config
# model = get_peft_model(model, lora_config)
# for name, param in model.named_parameters():
# if (
# "lora" in name
# ): # lm_head is not a parameter in most LLMs becasue it's tied to the embedding layer
# param.requires_grad = True
# else:
# param.requires_grad = False
# return model
def embed_tokens(self, tokens: torch.Tensor):
return self.pi0_paligemma.language_model.model.embed_tokens(tokens)
def prepare_inputs_for_generation(self, *args, **kwargs):
return self.pi0_paligemma.prepare_inputs_for_generation(*args, **kwargs)
def prepare_images(self, batch):
"""Preprocess LeRobot batch into Pi0 inputs"""
images = []
img_masks = []
img_keys = sorted(self.config.image_features.keys(), key=lambda k: IMAGES_ORDER.get(k, float("inf")))
present_img_keys = [key for key in self.config.image_features if key in batch]
# missing_img_keys = [key for key in self.config.image_features if key not in batch]
# present_img_keys = sorted(present_img_keys, key=lambda k: IMAGES_ORDER.get(k, float("inf")))
if len(present_img_keys) == 0:
raise ValueError(
f"All image features are missing from the batch. At least one expected. (batch: {batch.keys()}) (image_features:{self.config.image_features})"
)
# Preprocess image features present in the batch
num_empty_cameras = 0
for key in img_keys:
if key in present_img_keys:
img = batch[key]
if self.config.resize_imgs_with_padding is not None:
img = resize_with_pad(
img,
*self.config.resize_imgs_with_padding,
pad_value=0,
interpolate_like_pi=self.config.interpolate_like_pi,
)
# Normalize from range [0,1] to [-1,1] as expacted by siglip
img = img * 2.0 - 1.0
bsize = img.shape[0]
device = img.device
mask = torch.ones(bsize, dtype=torch.bool, device=device)
else:
if num_empty_cameras >= self.config.empty_cameras:
break
img = torch.ones_like(img) * -1
bsize = img.shape[0]
device = img.device
mask = torch.ones(bsize, dtype=torch.bool, device=device) # FIXME(mshukor): similar to openpi, but should be zeros?
# mask = torch.zeros(bsize, dtype=torch.bool, device=device)
# mask = torch.zeros_like(img)
# mask = torch.ones_like(mask)
num_empty_cameras += 1
images.append(img)
img_masks.append(mask)
return images, img_masks
def normalize_actions(self, actions: torch.Tensor) -> torch.Tensor:
mins = actions.amin(dim=(1, 2), keepdim=True) # [0]
maxs = actions.amax(dim=(1, 2), keepdim=True) # [0]
return 2 * (actions - mins) / (maxs - mins + 1e-8) - 1
def _act_tokens_to_paligemma_tokens1(self, tokens: torch.Tensor) -> torch.Tensor:
out = self.paligemma_tokenizer.vocab_size - 1 - self.fast_skip_tokens - tokens
return out
def fast_tokenizer_wrapper(self, actions_norm):
"""
A wrapper for self.fast_tokenizer that ensures batch processing,
conversion to PyTorch tensors, and returns a dictionary without padding.
"""
batch_tokens = self.fast_tokenizer(actions_norm)
fast_out = self.processor.tokenizer.pad({"input_ids": batch_tokens}, return_tensors="pt")
return fast_out
def create_token_type_ids(
self, padded_mask: torch.Tensor, prefix_len: int, action_kw_len: int, state_len: torch.Tensor, mode: str = "prefix"
) -> torch.Tensor:
token_type_ids = torch.zeros_like(padded_mask, dtype=torch.bool)
# Compute cumulative sum mask
cumsum_mask = (padded_mask != 0).cumsum(dim=1)
# Suffix block (everything after prefix_len)
suffix_mask = cumsum_mask > prefix_len
if mode == "block_causal":
# Start of state (only one position)
start_state_mask = cumsum_mask == (prefix_len - (action_kw_len + state_len))
# Start of action (only one position)
start_action_mask = cumsum_mask >= (prefix_len - action_kw_len)
# Combine the masks
token_type_ids = suffix_mask | start_state_mask | start_action_mask
else:
token_type_ids = suffix_mask
return token_type_ids
def create_input_tokens(self, state, lang_text, actions=None, action_kw_to_prefix: bool = True):
bsize = state.shape[0]
device = state.device
bins = torch.linspace(-1, 1, 256 + 1, device=device)[:-1]
discretized = torch.bucketize(state, bins) - 1
# TODO remove hardcoded parameter (32)
# discretized = F.pad(discretized, (0, max(0, 32 - discretized.shape[1])), value=0)[:, :32] # FIXME(mshukor): debug
discretized = discretized[:, :32]
prefix_texts = []
state_text = []
for txt, disc in zip(lang_text, discretized, strict=False):
cleaned = txt.lower().strip().replace("_", " ")
state_str = " ".join(str(val.item()) for val in disc)
if action_kw_to_prefix:
prefix_texts.append(f"Task: {cleaned}, State: {state_str};\nAction:")
else:
prefix_texts.append(f"Task: {cleaned}, State: {state_str};\n")
state_text.append(f"State: {state_str};\n")
prefix_out = self.paligemma_tokenizer(
prefix_texts, add_special_tokens=True, return_tensors="pt", padding="longest", truncation=False
)
prefix_ids = prefix_out["input_ids"].to(device)
prefix_mask = prefix_out["attention_mask"].to(device)
prefix_lens = prefix_mask.sum(dim=1)[:, None].cpu()
state_lens = self.paligemma_tokenizer(
state_text, add_special_tokens=False, return_tensors="pt", padding="longest", truncation=False
).attention_mask.sum(1)[:, None]
action_kw_len = torch.tensor([2])[:, None] if action_kw_to_prefix else torch.tensor([0])[:, None] # corresponds to["Action:"]
if actions is not None:
actions_norm = self.normalize_actions(actions)
actions_pad = F.pad(
actions_norm, (0, max(0, self.config.max_action_dim - actions_norm.shape[2])), value=0
)[:, :, : self.config.max_action_dim]
fast_out = self.fast_tokenizer_wrapper(
actions_pad.cpu(),
)
act_ids = fast_out["input_ids"]
act_mask = fast_out["attention_mask"].to(device)
act_ids = self._act_tokens_to_paligemma_tokens1(act_ids).to(device)
# replace action with 0 to pad tokens
act_ids = torch.where(
act_ids == self.paligemma_tokenizer.vocab_size - 1 - self.fast_skip_tokens,
self.pad_token_id,
act_ids,
)
eos_token = torch.tensor(
[self.paligemma_tokenizer.eos_token_id], dtype=torch.long, device=device
).expand(bsize, -1)
eos_mask = torch.tensor([1], dtype=torch.long, device=device).expand(bsize, -1)
if action_kw_to_prefix:
act_ids = torch.cat([act_ids, eos_token], dim=1)
act_mask = torch.cat([act_mask, eos_mask], dim=1)
else:
bos = self.paligemma_tokenizer('Action: ', add_special_tokens=False, return_tensors='pt')
bos_token = bos['input_ids'].expand(act_ids.shape[0],-1).to(device)
bos_mask = bos['attention_mask'].expand(act_ids.shape[0],-1).to(device)
#eos_mask = torch.ones_like(eos_token)
act_ids = torch.cat([bos_token, act_ids, eos_token], dim=1)
act_mask = torch.cat([bos_mask, act_mask, eos_mask], dim=1)
act_mask = act_mask.to(device)
else:
act_ids = torch.empty(bsize, self.pad_token_id, dtype=torch.long, device=device)
act_mask = torch.empty(bsize, 0, dtype=torch.long, device=device)
final_ids = torch.cat([prefix_ids, act_ids], dim=1) # act_ids already include postfix
final_mask = torch.cat([prefix_mask, act_mask], dim=1)
batch_inputs = {"input_ids": final_ids.tolist(), "attention_mask": final_mask.tolist()}
# Use tokenizer pad function
padded_output = self.paligemma_tokenizer.pad(
batch_inputs, padding="longest", max_length=180, return_tensors="pt"
)
padded_mask = padded_output["attention_mask"]
# define tensor of padding lengths
att_mask = (padded_mask != 0).cumsum(
dim=1
) > prefix_lens # [:, None].to(padded_mask.device) # need a batch indicator of prefix lengths OR NOT
token_type_ids = self.create_token_type_ids(
padded_mask=padded_mask, prefix_len=prefix_lens, action_kw_len=action_kw_len, state_len=state_lens, mode=self.config.attention_mode
)
padded_output["padded_mask"] = padded_output.pop("attention_mask")
padded_output["attention_mask"] = att_mask
# loss is computed not on prefix, and not on padding
padded_output["loss_mask"] = att_mask & padded_output["padded_mask"]
padded_output["token_type_ids"] = token_type_ids
return padded_output
def shift_padding_side(
self,
tokens: torch.Tensor,
ar_mask: torch.Tensor,
padding_mask: torch.Tensor,
loss_mask: torch.Tensor,
targets: torch.Tensor,
token_type_ids: torch.Tensor,
padding_side: str = "right",
) -> tuple[torch.Tensor]:
if padding_side not in ["right", "left"]:
return tokens, ar_mask, padding_mask, loss_mask, targets, token_type_ids
new_tokens = torch.empty_like(tokens)
new_ar_masks = torch.empty_like(ar_mask)
new_padding_mask = torch.empty_like(padding_mask)
new_loss_mask = torch.empty_like(loss_mask)
new_targets = torch.empty_like(targets)
new_token_type_ids = torch.empty_like(token_type_ids)
batch_size = tokens.shape[0]
for i in range(batch_size):
padding_indices = torch.where(padding_mask[i] == 0)[0]
non_padding_indices = torch.where(padding_mask[i] == 1)[0]
if padding_side == "left":
new_indices = torch.cat((padding_indices, non_padding_indices), dim=0)
else:
new_indices = torch.cat((non_padding_indices, padding_indices), dim=0)
new_tokens[i] = tokens[i].index_select(0, new_indices)
new_ar_masks[i] = ar_mask[i].index_select(0, new_indices)
new_padding_mask[i] = padding_mask[i].index_select(0, new_indices)
new_loss_mask[i] = loss_mask[i].index_select(0, new_indices)
new_targets[i] = targets[i].index_select(0, new_indices)
new_token_type_ids[i] = token_type_ids[i].index_select(0, new_indices)
return new_tokens, new_ar_masks, new_padding_mask, new_loss_mask, new_targets, new_token_type_ids
def forward(self, batch: dict[str, Tensor]):
device = batch[OBS_ROBOT].device
# TODO: keep like this or move to the policy .forward
images, img_masks = self.prepare_images(batch)
padded_outs = self.create_input_tokens(
state=batch[OBS_ROBOT], lang_text=batch["task"], actions=batch[ACTION], action_kw_to_prefix=self.config.action_kw_to_prefix,
)
embs, pad_masks, att_masks, targets, loss_mask, token_type_ids = self.embed_inputs(
images,
img_masks,
padded_outs["input_ids"],
padded_outs["padded_mask"],
padded_outs["attention_mask"],
padded_outs["loss_mask"],
padded_outs["token_type_ids"],
padding_side=self.padding_side,
)
position_ids = torch.cumsum(pad_masks, dim=1) - 1
token_type_ids = token_type_ids.to(dtype=torch.int64)
past_seen_tokens = 0
cache_position = torch.arange(past_seen_tokens, past_seen_tokens + embs.shape[1], device=embs.device)
pad_masks = block_causal_update_causal_mask(
attention_mask=pad_masks,
past_key_values=None,
cache_position=cache_position,
input_tensor=embs,
token_type_ids=token_type_ids,
dtype=self.pi0_paligemma.dtype,
attn_implementation=self.pi0_paligemma.config.text_config._attn_implementation,
)
outputs = self.pi0_paligemma.forward(
input_ids=None,
token_type_ids=None,
attention_mask=pad_masks,
position_ids=position_ids,
past_key_values=None,
inputs_embeds=embs,
use_cache=False,
labels=None,
)
logits = outputs.logits
loss_fct = nn.CrossEntropyLoss(reduction="none")
# Shift left for next-step prediction
logits = logits[:, :-1, :]
targets = targets[:, 1:].to(device) # Shift targets
loss_mask = loss_mask[:, 1:].to(device) # Ensure correct shape
# Compute per-token loss
token_loss = loss_fct(logits.reshape(-1, logits.shape[-1]), targets.reshape(-1))
# Apply loss mask
token_loss = token_loss * loss_mask.reshape(-1)
# Compute final loss
loss = token_loss.sum() / torch.clamp(loss_mask.sum(), min=1)
# Return loss dictionary
loss_dict = {"ce_loss": loss.item(), "loss": loss}
return loss_dict
def decode_actions_with_fast(
self,
tokens: list[list[int]],
*,
time_horizon: int | None = None,
action_dim: int | None = None,
) -> np.array:
self.time_horizon = (
time_horizon or self.fast_tokenizer.time_horizon or self.fast_tokenizer.called_time_horizon
)
self.action_dim = (
action_dim or self.fast_tokenizer.action_dim or self.fast_tokenizer.called_action_dim
)
# Cache the time horizon and action dimension for the next call
self.called_time_horizon = self.time_horizon
self.called_action_dim = self.action_dim
assert (
self.time_horizon is not None and self.action_dim is not None
), "Tokenizer not initialized, call encode() once or pass in time_horizon and action_dim."
decoded_actions = []
for token in tokens:
try:
decoded_tokens = self.fast_tokenizer.bpe_tokenizer.decode(token)
decoded_dct_coeff = np.array(list(map(ord, decoded_tokens))) + self.fast_tokenizer.min_token
# Expected sequence length
expected_seq_len = self.time_horizon * self.action_dim
diff = expected_seq_len - decoded_dct_coeff.shape[0]
# Apply truncation if too long
if diff < 0:
decoded_dct_coeff = decoded_dct_coeff[:expected_seq_len] # Truncate on the right
# Apply padding if too short
elif diff > 0:
decoded_dct_coeff = np.pad(
decoded_dct_coeff, (0, diff), mode="constant", constant_values=0
)
decoded_dct_coeff = decoded_dct_coeff.reshape(-1, self.action_dim)
assert (
decoded_dct_coeff.shape
== (
self.time_horizon,
self.action_dim,
)
), f"Decoded DCT coefficients have shape {decoded_dct_coeff.shape}, expected ({self.time_horizon}, {self.action_dim})"
except Exception as e:
print(f"Error decoding tokens: {e}")
print(f"Tokens: {token}")
decoded_dct_coeff = np.zeros((self.time_horizon, self.action_dim))
decoded_actions.append(idct(decoded_dct_coeff / self.fast_tokenizer.scale, axis=0, norm="ortho"))
return np.stack(decoded_actions)
def extract_actions(self, tokens: torch.Tensor, action_horizon: int, action_dim: int) -> torch.Tensor:
"""
Extracts actions from predicted output tokens using the FAST model.
Args:
tokens (torch.Tensor): The input tensor of tokenized outputs.
action_horizon (int): The number of timesteps for actions.
action_dim (int): The dimensionality of each action.
Returns:
torch.Tensor: The extracted actions as a tensor of shape (action_horizon, action_dim).
"""
# Decode predicted output tokens
decoded_tokens = self.paligemma_tokenizer.batch_decode(tokens, skip_special_tokens=True)
cleaned_tokens = [
tokens_sequence.replace(":", "").strip().split("|")[0].strip()
for tokens_sequence in decoded_tokens
] # should work
# TODO: for now let's use the processor tokenizer which encodes in the way we want (it is different from tusing the AutoTokenizer for some reasons)
raw_action_tokens = [
self.processor.tokenizer.encode(sample_tokens, return_tensors="pt", padding=False)
for sample_tokens in cleaned_tokens
] # something like this should be robust #looks good
action_tokens = [
self._act_tokens_to_paligemma_tokens1(raw_action_token) for raw_action_token in raw_action_tokens
]
# returns the tensor of decoded actions per sample in a list
decoded_actions = [
torch.tensor(
self.decode_actions_with_fast(
tok.tolist(), time_horizon=action_horizon, action_dim=action_dim
),
device=tokens.device,
).squeeze(0)
for tok in action_tokens
]
return torch.stack(
decoded_actions,
dim=0,
)
def generate_actions(self, batch: dict[str, Tensor]):
# TODO: keep like this or move to the policy .forward
images, img_masks = self.prepare_images(batch)
padded_outs = self.create_input_tokens(state=batch[OBS_ROBOT], lang_text=batch["task"], actions=None, action_kw_to_prefix=self.config.action_kw_to_prefix)
embs, pad_masks, att_masks2, targets, loss_mask, token_type_ids = self.embed_inputs(
images,
img_masks,
padded_outs["input_ids"],
padded_outs["padded_mask"],
padded_outs["attention_mask"],
padded_outs["loss_mask"],
padded_outs["token_type_ids"],
padding_side="left",
)
token_type_ids = token_type_ids.to(dtype=torch.int64)
prefix_position_ids = torch.cumsum(pad_masks, dim=1) - 1
output_tokens = self.pi0_paligemma.generate(
input_ids=None,
attention_mask=pad_masks,
position_ids=prefix_position_ids,
past_key_values=None,
inputs_embeds=embs, # No need for [prefix_embs, None]
use_cache=self.config.use_cache,
max_new_tokens=self.config.max_decoding_steps,
do_sample=False,
num_beams=1,
token_type_ids=token_type_ids,
)
# import ipdb; ipdb.set_trace()
actions = self.extract_actions(output_tokens, self.action_horizon, self.action_dim)
return actions
# TODO: remove? seems uneeded
def embed_image(self, image: torch.Tensor):
return self.pi0_paligemma.get_image_features(image)
def embed_inputs(
self,
images,
img_masks,
tokens,
pad_mask,
ar_mask,
loss_mask,
token_type_ids,
padding_side: str = "right",
):
# TODO: avoid list in python and torch.cat ; prefer pre-allocation with torch.empty
# images are a list of same size
# vectorizing everything!
device = images[0].device
image_embedding_dim = images[0].shape[-1] # TODO should be from self.config
all_images = torch.stack(images, dim=1).to(device)
b, n, c, h, w = all_images.shape
all_images = all_images.view(b * n, c, h, w)
embedded = self.embed_image(all_images).to(device)
b_n, p, image_embedding_dim = embedded.shape # Extract current dimensions
m = b_n // b # Compute the number of images per sample dynamically
# Reshape dynamically
embedded = embedded.view(b, m, p, image_embedding_dim)
tokens_embs = self.embed_tokens(tokens.to(device))
img_masks = torch.stack(img_masks, dim=1).unsqueeze(-1).to(device)
num_img_emb = embedded.shape[2]
img_pad_masks = img_masks.repeat(1, 1, num_img_emb).view(b, -1)
img_att_masks = torch.zeros((b, n, num_img_emb), dtype=torch.long, device=device).reshape(b, -1)
image_target_tokens = (
torch.ones((b, n, num_img_emb), dtype=torch.long, device=device) * self.pad_token_id
).reshape(b, -1)
image_loss_mask = torch.zeros((b, n, num_img_emb), dtype=torch.long, device=device).reshape(b, -1)
embedded = embedded.reshape(b, n * num_img_emb, image_embedding_dim) # Shape: (B, N*P, D)
embs = torch.cat([embedded, tokens_embs], dim=1).to(device)
pad_masks = torch.cat([img_pad_masks, pad_mask.to(device)], dim=1)
att_masks = torch.cat([img_att_masks, ar_mask.to(device)], dim=1)
loss_masks = torch.cat([image_loss_mask, loss_mask.to(device)], dim=1)
targets = torch.cat([image_target_tokens, tokens.to(device)], dim=1)
token_type_ids = torch.cat([img_att_masks, token_type_ids.to(device)], dim=1)
# Shift pad tokens to the left (.generate()) or right (.train())
embs, att_masks, pad_masks, loss_masks, targets, token_type_ids = self.shift_padding_side(
embs, att_masks, pad_masks, loss_masks, targets, token_type_ids, padding_side=padding_side
)
targets = torch.where(targets == self.pad_token_id, self.ignore_index, targets)
return embs, pad_masks, att_masks, targets, loss_masks, token_type_ids
def resize_with_pad(img, width, height, pad_value=0, interpolate_like_pi=True):
# assume no-op when width height fits already
if img.ndim != 4:
raise ValueError(f"(b,c,h,w) expected, but {img.shape}")
cur_height, cur_width = img.shape[2:]
ratio = max(cur_width / width, cur_height / height)
resized_height = int(cur_height / ratio)
resized_width = int(cur_width / ratio)
if interpolate_like_pi:
img = (img * 255.0).to(dtype=torch.uint8)
img = img.permute(0, 2, 3, 1)
original_device = img.device
img = img.to(device="cpu").numpy()
imgs = []
for sub_img in img:
sub_img = Image.fromarray(sub_img)
resized_img = sub_img.resize((resized_width, resized_height), resample=2)
resized_img = torch.from_numpy(np.array(resized_img))
imgs.append(resized_img)
img = torch.stack(imgs, dim=0)
img = img.permute(0, 3, 1, 2)
resized_img = img.to(device=original_device, dtype=torch.float32) / 255.0
else:
resized_img = F.interpolate(
img, size=(resized_height, resized_width), mode="bilinear", align_corners=False
)
pad_height = max(0, int(height - resized_height))
pad_width = max(0, int(width - resized_width))
# pad on left and top of image
padded_img = F.pad(resized_img, (pad_width, 0, pad_height, 0), value=pad_value)
return padded_img
def pad_vector(vector, new_dim):
"""Can be (batch_size x sequence_length x features_dimension)
or (batch_size x features_dimension)
"""
if vector.shape[-1] == new_dim:
return vector
shape = list(vector.shape)
current_dim = shape[-1]
shape[-1] = new_dim
new_vector = torch.zeros(*shape, dtype=vector.dtype, device=vector.device)
new_vector[..., :current_dim] = vector
return new_vector