147 lines
4.5 KiB
Python
147 lines
4.5 KiB
Python
#!/usr/bin/env python
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# __tutorial_imports_begin__
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import argparse
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import os
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import numpy as np
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import torch
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import torch.optim as optim
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import ray
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from ray import tune
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from ray.tune import Checkpoint
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from ray.tune.examples.mnist_pytorch import ConvNet, get_data_loaders, test_func
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from ray.tune.schedulers import PopulationBasedTraining
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# __tutorial_imports_end__
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# __train_begin__
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def train_convnet(config):
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# Create our data loaders, model, and optmizer.
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step = 0
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train_loader, test_loader = get_data_loaders()
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model = ConvNet()
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optimizer = optim.SGD(
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model.parameters(),
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lr=config.get("lr", 0.01),
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momentum=config.get("momentum", 0.9),
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)
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# If `get_checkpoint()` is not None, then we are resuming from a checkpoint.
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# Load model state and iteration step from checkpoint.
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if tune.get_checkpoint():
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print("Loading from checkpoint.")
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loaded_checkpoint = tune.get_checkpoint()
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with loaded_checkpoint.as_directory() as loaded_checkpoint_dir:
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path = os.path.join(loaded_checkpoint_dir, "checkpoint.pt")
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checkpoint = torch.load(path)
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model.load_state_dict(checkpoint["model"])
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step = checkpoint["step"]
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while True:
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ray.tune.examples.mnist_pytorch.train_func(model, optimizer, train_loader)
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acc = test_func(model, test_loader)
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checkpoint = None
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if step % 5 == 0:
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# Every 5 steps, checkpoint our current state.
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# First get the checkpoint directory from tune.
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# Need to create a directory under current working directory
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# to construct checkpoint object from.
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os.makedirs("my_model", exist_ok=True)
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torch.save(
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{
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"step": step,
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"model": model.state_dict(),
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},
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"my_model/checkpoint.pt",
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)
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checkpoint = Checkpoint.from_directory("my_model")
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step += 1
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tune.report({"mean_accuracy": acc}, checkpoint=checkpoint)
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# __train_end__
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def eval_best_model(results: tune.ResultGrid):
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"""Test the best model given output of tuner.fit()."""
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with results.get_best_result().checkpoint.as_directory() as best_checkpoint_path:
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best_model = ConvNet()
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best_checkpoint = torch.load(
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os.path.join(best_checkpoint_path, "checkpoint.pt")
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)
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best_model.load_state_dict(best_checkpoint["model"])
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# Note that test only runs on a small random set of the test data, thus the
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# accuracy may be different from metrics shown in tuning process.
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test_acc = test_func(best_model, get_data_loaders()[1])
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print("best model accuracy: ", test_acc)
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if __name__ == "__main__":
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parser = argparse.ArgumentParser()
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parser.add_argument(
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"--smoke-test", action="store_true", help="Finish quickly for testing"
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)
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args, _ = parser.parse_known_args()
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# __pbt_begin__
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scheduler = PopulationBasedTraining(
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time_attr="training_iteration",
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perturbation_interval=5,
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hyperparam_mutations={
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# distribution for resampling
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"lr": lambda: np.random.uniform(0.0001, 1),
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# allow perturbations within this set of categorical values
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"momentum": [0.8, 0.9, 0.99],
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},
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)
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# __pbt_end__
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# __tune_begin__
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class CustomStopper(tune.Stopper):
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def __init__(self):
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self.should_stop = False
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def __call__(self, trial_id, result):
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max_iter = 5 if args.smoke_test else 100
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if not self.should_stop and result["mean_accuracy"] > 0.96:
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self.should_stop = True
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return self.should_stop or result["training_iteration"] >= max_iter
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def stop_all(self):
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return self.should_stop
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stopper = CustomStopper()
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tuner = tune.Tuner(
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train_convnet,
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run_config=tune.RunConfig(
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name="pbt_test",
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stop=stopper,
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verbose=1,
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checkpoint_config=tune.CheckpointConfig(
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checkpoint_score_attribute="mean_accuracy",
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num_to_keep=4,
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),
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),
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tune_config=tune.TuneConfig(
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scheduler=scheduler,
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metric="mean_accuracy",
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mode="max",
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num_samples=4,
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reuse_actors=True,
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),
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param_space={
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"lr": tune.uniform(0.001, 1),
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"momentum": tune.uniform(0.001, 1),
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},
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)
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results = tuner.fit()
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# __tune_end__
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eval_best_model(results)
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