Spaces:
Running
on
Zero
Running
on
Zero
File size: 6,033 Bytes
62c110b |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 |
# Copyright 2024 The HuggingFace 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.
import numpy as np
import torch
import tqdm
from ...models.unets.unet_1d import UNet1DModel
from ...pipelines import DiffusionPipeline
from ...utils.dummy_pt_objects import DDPMScheduler
from ...utils.torch_utils import randn_tensor
class ValueGuidedRLPipeline(DiffusionPipeline):
r"""
Pipeline for value-guided sampling from a diffusion model trained to predict sequences of states.
This model inherits from [`DiffusionPipeline`]. Check the superclass documentation for the generic methods
implemented for all pipelines (downloading, saving, running on a particular device, etc.).
Parameters:
value_function ([`UNet1DModel`]):
A specialized UNet for fine-tuning trajectories base on reward.
unet ([`UNet1DModel`]):
UNet architecture to denoise the encoded trajectories.
scheduler ([`SchedulerMixin`]):
A scheduler to be used in combination with `unet` to denoise the encoded trajectories. Default for this
application is [`DDPMScheduler`].
env ():
An environment following the OpenAI gym API to act in. For now only Hopper has pretrained models.
"""
def __init__(
self,
value_function: UNet1DModel,
unet: UNet1DModel,
scheduler: DDPMScheduler,
env,
):
super().__init__()
self.register_modules(value_function=value_function, unet=unet, scheduler=scheduler, env=env)
self.data = env.get_dataset()
self.means = {}
for key in self.data.keys():
try:
self.means[key] = self.data[key].mean()
except: # noqa: E722
pass
self.stds = {}
for key in self.data.keys():
try:
self.stds[key] = self.data[key].std()
except: # noqa: E722
pass
self.state_dim = env.observation_space.shape[0]
self.action_dim = env.action_space.shape[0]
def normalize(self, x_in, key):
return (x_in - self.means[key]) / self.stds[key]
def de_normalize(self, x_in, key):
return x_in * self.stds[key] + self.means[key]
def to_torch(self, x_in):
if isinstance(x_in, dict):
return {k: self.to_torch(v) for k, v in x_in.items()}
elif torch.is_tensor(x_in):
return x_in.to(self.unet.device)
return torch.tensor(x_in, device=self.unet.device)
def reset_x0(self, x_in, cond, act_dim):
for key, val in cond.items():
x_in[:, key, act_dim:] = val.clone()
return x_in
def run_diffusion(self, x, conditions, n_guide_steps, scale):
batch_size = x.shape[0]
y = None
for i in tqdm.tqdm(self.scheduler.timesteps):
# create batch of timesteps to pass into model
timesteps = torch.full((batch_size,), i, device=self.unet.device, dtype=torch.long)
for _ in range(n_guide_steps):
with torch.enable_grad():
x.requires_grad_()
# permute to match dimension for pre-trained models
y = self.value_function(x.permute(0, 2, 1), timesteps).sample
grad = torch.autograd.grad([y.sum()], [x])[0]
posterior_variance = self.scheduler._get_variance(i)
model_std = torch.exp(0.5 * posterior_variance)
grad = model_std * grad
grad[timesteps < 2] = 0
x = x.detach()
x = x + scale * grad
x = self.reset_x0(x, conditions, self.action_dim)
prev_x = self.unet(x.permute(0, 2, 1), timesteps).sample.permute(0, 2, 1)
# TODO: verify deprecation of this kwarg
x = self.scheduler.step(prev_x, i, x)["prev_sample"]
# apply conditions to the trajectory (set the initial state)
x = self.reset_x0(x, conditions, self.action_dim)
x = self.to_torch(x)
return x, y
def __call__(self, obs, batch_size=64, planning_horizon=32, n_guide_steps=2, scale=0.1):
# normalize the observations and create batch dimension
obs = self.normalize(obs, "observations")
obs = obs[None].repeat(batch_size, axis=0)
conditions = {0: self.to_torch(obs)}
shape = (batch_size, planning_horizon, self.state_dim + self.action_dim)
# generate initial noise and apply our conditions (to make the trajectories start at current state)
x1 = randn_tensor(shape, device=self.unet.device)
x = self.reset_x0(x1, conditions, self.action_dim)
x = self.to_torch(x)
# run the diffusion process
x, y = self.run_diffusion(x, conditions, n_guide_steps, scale)
# sort output trajectories by value
sorted_idx = y.argsort(0, descending=True).squeeze()
sorted_values = x[sorted_idx]
actions = sorted_values[:, :, : self.action_dim]
actions = actions.detach().cpu().numpy()
denorm_actions = self.de_normalize(actions, key="actions")
# select the action with the highest value
if y is not None:
selected_index = 0
else:
# if we didn't run value guiding, select a random action
selected_index = np.random.randint(0, batch_size)
denorm_actions = denorm_actions[selected_index, 0]
return denorm_actions
|