Init
This commit is contained in:
Starrick
Executable
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import math
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import torch
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import torch.nn as nn
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from torch.distributions import Beta
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from wall_x.utils.constant import action_statistic_dof
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class Normalizer(nn.Module):
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"""
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Action data normalizer for multi-robot systems.
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This module handles normalization and denormalization of action data for different robot
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configurations. It maintains per-robot statistics (min values and deltas) and applies
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normalization to map actions to the [-1, 1] range.
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"""
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def __init__(self, action_statistic_dof, dof_config):
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"""
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Initialize the normalizer with robot-specific action statistics.
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Args:
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action_statistic_dof (dict): Statistical data for each robot's degrees of freedom
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dof_config (dict): Configuration mapping for degrees of freedom per robot
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"""
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super(Normalizer, self).__init__()
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action_statistic = {}
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# Process statistics for each robot
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for robot_name in action_statistic_dof.keys():
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action_statistic[robot_name] = {}
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all_dof_min = []
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all_dof_delta = []
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# Collect min and delta values for all DOFs
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for k in dof_config:
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if k in action_statistic_dof[robot_name]:
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all_dof_min.extend(action_statistic_dof[robot_name][k]["min"])
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all_dof_delta.extend(action_statistic_dof[robot_name][k]["delta"])
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else:
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# Use default values if statistics not available
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all_dof_min.extend([0.0] * dof_config[k])
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all_dof_delta.extend([1.0] * dof_config[k])
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all_dof_min = torch.tensor(all_dof_min)
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all_dof_delta = torch.tensor(all_dof_delta)
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action_statistic[robot_name]["min"] = all_dof_min
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action_statistic[robot_name]["delta"] = all_dof_delta
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# Register statistics as non-trainable parameters
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self.min = nn.ParameterDict({
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k: nn.Parameter(action_statistic[k]["min"], requires_grad=False)
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for k in action_statistic.keys()
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})
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self.delta = nn.ParameterDict({
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k: nn.Parameter(action_statistic[k]["delta"], requires_grad=False)
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for k in action_statistic.keys()
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})
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def normalize_data(self, xs, dataset_names):
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"""
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Normalize action data to [-1, 1] range using robot-specific statistics.
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Args:
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xs: Input action data tensors
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dataset_names: List of dataset/robot names corresponding to each tensor
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Returns:
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torch.Tensor: Normalized action data in [-1, 1] range
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"""
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new_xs = []
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# Filter out multimodal dataset entries
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dataset_names = [name for name in dataset_names if name != "x2_multimodal"]
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for x, dataset_name in zip(xs, dataset_names):
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# Apply min-max normalization
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x = (x - self.min[dataset_name]) / (self.delta[dataset_name])
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# Scale to [-1, 1] range
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x = x * 2 - 1
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# Clamp to ensure bounds
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x = torch.clamp(x, -1, 1)
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new_xs.append(x)
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new_xs = torch.stack(new_xs)
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return new_xs
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def unnormalize_data(self, xs, dataset_names, dof_mask=None):
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"""
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Convert normalized data back to original action space.
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Args:
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xs: Normalized action data in [-1, 1] range
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dataset_names: List of dataset/robot names
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dof_mask: Optional mask to select specific degrees of freedom
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Returns:
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torch.Tensor: Denormalized action data in original scale
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"""
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new_xs = []
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# Filter out multimodal dataset entries
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dataset_names = [name for name in dataset_names if name != "x2_multimodal"]
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dof_mask = dof_mask if dof_mask is not None else [None] * len(xs)
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for x, dataset_name, mask in zip(xs, dataset_names, dof_mask):
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# Convert from [-1, 1] to [0, 1] range
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x = (x + 1) / 2
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# Apply DOF mask if provided
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if mask is not None:
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mask = mask[0].bool()
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action_space_delta = self.delta[dataset_name][mask]
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action_space_min = self.min[dataset_name][mask]
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else:
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action_space_delta = self.delta[dataset_name]
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action_space_min = self.min[dataset_name]
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# Scale back to original range
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x = x * action_space_delta + action_space_min
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new_xs.append(x)
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new_xs = torch.stack(new_xs)
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return new_xs
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class SinusoidalPosEmb(nn.Module):
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"""
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Sinusoidal positional embedding for diffusion timesteps.
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Generates sinusoidal embeddings commonly used in diffusion models to encode
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timestep information with different frequencies.
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"""
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def __init__(self, dim):
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"""
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Initialize sinusoidal positional embedding.
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Args:
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dim (int): Embedding dimension (must be even)
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"""
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super().__init__()
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self.dim = dim
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def forward(self, x):
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"""
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Generate sinusoidal embeddings for input timesteps.
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Args:
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x (torch.Tensor): Input timesteps
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Returns:
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torch.Tensor: Sinusoidal embeddings of shape (..., dim)
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"""
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device = x.device
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half_dim = self.dim // 2
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emb = math.log(10000) / (half_dim - 1)
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emb = torch.exp(torch.arange(half_dim, device=device) * -emb)
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emb = x[:, None] * emb[None, :]
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emb = torch.cat((emb.sin(), emb.cos()), dim=-1)
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return emb
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class ActionProcessor(nn.Module):
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"""
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Action sequence processor for robotic control with flow matching.
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This module handles action sequence processing for robotic systems with the following capabilities:
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1. Adds controlled noise to action sequences using Beta distribution scheduling
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2. Generates temporal embeddings for timestep conditioning
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3. Projects actions to model hidden space for transformer processing
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4. Supports proprioceptive data integration and multi-robot configurations
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The Beta distribution provides more flexible noise injection strategies compared to
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traditional linear schedules, allowing better control over the noise scheduling process.
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"""
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def __init__(self, config):
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"""
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Initialize the action processor with multi-robot support.
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Args:
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config: Configuration object containing:
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- dof_config (dict): Degrees of freedom configuration per robot type
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- agent_pos_config (dict): Agent position/proprioception configuration
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- hidden_size (int): Model hidden layer dimension
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- noise_scheduler (dict): Noise scheduler configuration with Beta parameters
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"""
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super().__init__()
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# Calculate action and proprioception dimensions from configuration
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self.dof_config = config.dof_config
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self.agent_pos_config = config.agent_pos_config
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self.action_dim = sum([v for k, v in self.dof_config.items()])
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self.propri_dim = sum([v for k, v in self.agent_pos_config.items()])
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# Log configuration details for debugging
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print("ActionProcessor Configuration:", flush=True)
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print(f" Action dimension: {self.action_dim}", flush=True)
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print(f" Proprioception dimension: {self.propri_dim}", flush=True)
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print(" DOF configuration:", flush=True)
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for key, value in self.dof_config.items():
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print(f" {key}: {value}", flush=True)
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print(" Agent position configuration:", flush=True)
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for key, value in self.agent_pos_config.items():
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print(f" {key}: {value}", flush=True)
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self.hidden_size = config.hidden_size
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# Initialize data normalizers for actions and proprioception
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self.normalizer_action = Normalizer(action_statistic_dof, config.dof_config)
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self.normalizer_propri = Normalizer(action_statistic_dof, config.agent_pos_config)
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# Proprioception projection layer (includes history/current state)
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self.propri_proj = nn.Linear(self.propri_dim * 2, self.hidden_size, bias=False)
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# Beta distribution noise scheduler configuration
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noise_scheduler_config = config.noise_scheduler
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self.beta_alpha = noise_scheduler_config.get('beta_alpha', 1.5) # Beta distribution α parameter
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self.beta_beta = noise_scheduler_config.get('beta_beta', 1.0) # Beta distribution β parameter
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self.s = noise_scheduler_config.get('s', 0.999) # Scaling factor
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# Initialize Beta distribution for noise scheduling
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alpha_tensor = torch.tensor(self.beta_alpha, dtype=torch.float32).to("cuda")
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beta_tensor = torch.tensor(self.beta_beta, dtype=torch.float32).to("cuda")
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self.beta_dist = Beta(alpha_tensor, beta_tensor)
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# Sinusoidal positional embedding for timesteps
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self.time_embed = SinusoidalPosEmb(config.hidden_size)
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# Action embedding network: project to hidden space
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self.w1 = nn.Linear(self.action_dim * 2, self.hidden_size, bias=False) # *2 for action + DOF mask
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self.w2 = nn.Linear(self.hidden_size * 2, self.hidden_size, bias=False) # *2 for action + time embeddings
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self.w3 = nn.Linear(self.hidden_size, self.hidden_size, bias=False)
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self.act_fn = nn.SiLU()
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# Project back to action space for flow matching loss
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self.action_proj_back = nn.Linear(self.hidden_size, self.action_dim, bias=False)
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self.mse_loss = nn.MSELoss(reduction='none')
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def sample_time(self, batch_size, device, dtype):
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"""
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Sample timesteps using Beta distribution for noise scheduling.
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Generates random timesteps in [0,1] range using Beta distribution, then scales them.
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This provides more flexible control over the noise injection schedule compared to
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uniform sampling.
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Args:
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batch_size (int): Number of timesteps to sample
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device: Target device for tensors
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dtype: Target data type for tensors
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Returns:
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torch.Tensor: Sampled timesteps of shape [batch_size]
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"""
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sample = self.beta_dist.sample([batch_size]).to(device=device, dtype=dtype)
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time = (self.s - sample) / self.s
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return time
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def proprioception_proj(self, proprioception, dataset_names=None, dof_mask=None, use_history=False):
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"""
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Project proprioceptive data (joint positions, orientations) to hidden space.
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Args:
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proprioception (torch.Tensor): Proprioceptive data of shape [batch_size, seq_len, propri_dim]
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dataset_names (list, optional): Dataset names for normalization. Defaults to None.
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dof_mask (torch.Tensor, optional): DOF mask of shape [batch_size, propri_dim]. Defaults to None.
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use_history (bool, optional): Whether to use historical proprioceptive data. Defaults to False.
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Returns:
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torch.Tensor: Projected proprioceptive features of shape [batch_size, seq_len, hidden_size]
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"""
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# Ensure proper device and dtype alignment
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proprioception = proprioception.to(device=self.propri_proj.weight.device).to(dtype=self.propri_proj.weight.dtype)
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if dof_mask is not None:
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# Concatenate proprioception with DOF mask
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# TODO: Use variable-based dimension checking for better flexibility
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if use_history:
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proprioception = torch.cat([proprioception, dof_mask], dim=-1)
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else:
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proprioception = torch.cat([proprioception, dof_mask], dim=-1)
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proprioception = proprioception.to(device=self.propri_proj.weight.device).to(dtype=self.propri_proj.weight.dtype)
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return self.propri_proj(proprioception)
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def forward(self, action_chunk, dataset_names, dof_mask=None):
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"""
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Process action sequences with noise injection and temporal embedding.
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This method implements the forward pass for flow matching training:
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1. Adds Beta-distributed noise to action sequences
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2. Generates sinusoidal timestep embeddings
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3. Projects noisy actions to hidden space
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4. Combines action and temporal features
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Args:
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action_chunk (torch.Tensor): Action sequences of shape [batch_size, seq_len, action_dim]
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dataset_names (list): Dataset names for normalization
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dof_mask (torch.Tensor, optional): DOF mask of shape [batch_size, seq_len, action_dim].
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Defaults to None.
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Returns:
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tuple: (action_embeddings, flow_target) where:
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- action_embeddings: Processed action features of shape [batch_size, seq_len, hidden_size]
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- flow_target: Flow matching target (action_chunk - noise) for loss computation
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"""
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batch_size = action_chunk.shape[0]
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device = action_chunk.device
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dtype = action_chunk.dtype
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# 1. Add noise to action sequences using flow matching
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noise = torch.randn_like(action_chunk)
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time = self.sample_time(batch_size, device, dtype)
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t = time.unsqueeze(-1).unsqueeze(-1) # Broadcast to match action dimensions
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# Linear interpolation between noise and action (flow matching)
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noisy_action = (1 - t) * noise + t * action_chunk
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flow = action_chunk - noise # Flow target for loss computation
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# 2. Generate sinusoidal positional encoding for timesteps
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time_embed = self.time_embed(time)
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# 3. Project noisy actions with DOF mask to hidden space
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if dof_mask is not None:
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noisy_action = torch.cat([noisy_action, dof_mask], dim=-1)
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noisy_action = noisy_action.to(dtype=self.w1.weight.dtype)
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action_embed = self.w1(noisy_action)
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# Repeat time embedding for each sequence position
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time_embed = time_embed.unsqueeze(1).repeat(1, action_embed.shape[1], 1).to(dtype=self.w2.weight.dtype)
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# Combine action and temporal embeddings
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concat_embed = torch.cat([action_embed, time_embed], dim=-1)
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concat_embed = self.w2(concat_embed)
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embed = self.w3(self.act_fn(concat_embed))
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return embed, flow
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def step(self, timestep, noisy_action, dof_mask=None):
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"""
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Single denoising step for diffusion inference.
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Processes noisy actions at a specific timestep for iterative denoising during inference.
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Args:
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timestep (torch.Tensor): Current timesteps of shape [batch_size]
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noisy_action (torch.Tensor): Noisy actions of shape [batch_size, seq_len, action_dim]
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dof_mask (torch.Tensor, optional): DOF mask for action space. Defaults to None.
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Returns:
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torch.Tensor: Processed action embeddings of shape [batch_size, seq_len, hidden_size]
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"""
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# Concatenate noisy action with DOF mask if provided
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if dof_mask is not None:
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noisy_action = torch.cat([noisy_action, dof_mask], dim=-1)
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# Generate timestep embeddings
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time_embed = self.time_embed(timestep) # [batch_size, hidden_size]
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# Project noisy actions
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action_embed = self.w1(noisy_action)
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# Broadcast time embeddings to sequence length
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time_embed = time_embed.unsqueeze(1).repeat(1, action_embed.shape[1], 1)
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time_embed = time_embed.to(device=noisy_action.device).to(dtype=noisy_action.dtype)
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# Combine embeddings and process through MLP
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concat_embed = torch.cat([action_embed, time_embed], dim=-1)
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concat_embed = self.w2(concat_embed)
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embed = self.w3(self.act_fn(concat_embed))
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return embed
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def flow_loss(self, action_hidden_states, flow, dof_mask=None):
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"""
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Compute flow matching loss between predicted and target actions.
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Args:
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action_hidden_states (torch.Tensor): Hidden states from transformer
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flow (torch.Tensor): Target flow (action - noise) for matching
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dof_mask (torch.Tensor, optional): DOF mask to weight loss per dimension. Defaults to None.
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Returns:
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torch.Tensor: Flow matching loss (no reduction for channel loss computation)
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"""
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# Project hidden states back to action space
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action_pred = self.action_proj_back(action_hidden_states)
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# Compute MSE loss between predicted and target flow
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loss = self.mse_loss(action_pred, flow)
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# Apply DOF mask if provided
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if dof_mask is not None:
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dof_mask = dof_mask.reshape(-1, dof_mask.shape[-1])
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loss = loss * dof_mask
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# Return loss without reduction for channel-wise loss computation
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return loss
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