Files
ray-project--ray/python/ray/train/v2/tests/test_lightgbm_trainer.py
T
2026-07-13 13:17:40 +08:00

152 lines
5.1 KiB
Python

import math
import lightgbm
import pandas as pd
import pytest
from sklearn.datasets import load_breast_cancer
from sklearn.model_selection import train_test_split
import ray
import ray.data
from ray.train import ScalingConfig
from ray.train.constants import TRAIN_DATASET_KEY
from ray.train.lightgbm import (
LightGBMTrainer,
RayTrainReportCallback,
normalize_pandas_for_lightgbm,
)
from ray.train.v2._internal.constants import is_v2_enabled
assert is_v2_enabled()
@pytest.fixture
def ray_start_6_cpus():
address_info = ray.init(num_cpus=6)
yield address_info
# The code after the yield will run as teardown code.
ray.shutdown()
scale_config = ScalingConfig(num_workers=2)
data_raw = load_breast_cancer()
dataset_df = pd.DataFrame(data_raw["data"], columns=data_raw["feature_names"])
dataset_df["target"] = data_raw["target"]
train_df, test_df = train_test_split(dataset_df, test_size=0.3)
params = {
"objective": "binary",
"metric": ["binary_logloss", "binary_error"],
}
def test_fit_with_categoricals(ray_start_6_cpus):
@ray.remote
class ValidationCollector:
def __init__(self):
self.validation_scores = {}
def report(self, rank, binary_logloss, binary_error):
self.validation_scores[rank] = {
"binary_logloss": binary_logloss,
"binary_error": binary_error,
}
def get_validation_scores(self):
return self.validation_scores
# Ensure all workers have the same model in data parallel training
# by comparing their validation scores.
# Comparing lightgbm models directly seems less reliable.
collector = ValidationCollector.remote()
def lightgbm_train_fn_per_worker(
config: dict,
label_column: str,
valid_dataset: ray.data.Dataset,
num_boost_round: int = 10,
):
remaining_iters = num_boost_round
train_ds_iter = ray.train.get_dataset_shard(TRAIN_DATASET_KEY)
train_df = normalize_pandas_for_lightgbm(
train_ds_iter.materialize().to_pandas()
)
eval_df = normalize_pandas_for_lightgbm(valid_dataset.materialize().to_pandas())
eval_X, eval_y = eval_df.drop(label_column, axis=1), eval_df[label_column]
valid_set = lightgbm.Dataset(eval_X, label=eval_y)
train_X, train_y = train_df.drop(label_column, axis=1), train_df[label_column]
train_set = lightgbm.Dataset(train_X, label=train_y)
# Add network params of the worker group to enable distributed training.
config.update(ray.train.lightgbm.get_network_params())
# Add lightgbm-specific distributed training params.
config.update(
{
"tree_learner": "data_parallel",
"pre_partition": True,
}
)
booster = lightgbm.train(
params=config,
train_set=train_set,
num_boost_round=remaining_iters,
# NOTE: Include the training dataset in the evaluation datasets.
# This allows `train-*` metrics to be calculated and reported.
valid_sets=[valid_set, train_set],
valid_names=["valid", TRAIN_DATASET_KEY],
init_model=None,
callbacks=[RayTrainReportCallback()],
)
collector.report.remote(
ray.train.get_context().get_world_rank(),
booster.best_score["valid"]["binary_logloss"],
booster.best_score["valid"]["binary_error"],
)
train_df_with_cat = train_df.copy()
test_df_with_cat = test_df.copy()
train_df_with_cat["categorical_column"] = pd.Series(
(["A", "B"] * math.ceil(len(train_df_with_cat) / 2))[: len(train_df_with_cat)]
).astype("category")
test_df_with_cat["categorical_column"] = pd.Series(
(["A", "B"] * math.ceil(len(test_df_with_cat) / 2))[: len(test_df_with_cat)]
).astype("category")
train_dataset = ray.data.from_pandas(train_df_with_cat)
valid_dataset = ray.data.from_pandas(test_df_with_cat)
trainer = LightGBMTrainer(
train_loop_per_worker=lambda: lightgbm_train_fn_per_worker(
config=params,
label_column="target",
# Do not shard the validation dataset across workers to ensure all workers compute
# the same validation score. See https://github.com/microsoft/LightGBM/issues/4392.
valid_dataset=valid_dataset,
),
scaling_config=scale_config,
datasets={TRAIN_DATASET_KEY: train_dataset},
)
result = trainer.fit()
checkpoint = result.checkpoint
model = RayTrainReportCallback.get_model(checkpoint)
assert model.pandas_categorical == [["A", "B"]]
validation_scores = ray.get(collector.get_validation_scores.remote())
assert validation_scores[0]["binary_logloss"] == pytest.approx(
validation_scores[1]["binary_logloss"], abs=1e-6
)
assert validation_scores[0]["binary_error"] == pytest.approx(
validation_scores[1]["binary_error"], abs=1e-6
)
if __name__ == "__main__":
import sys
import pytest
sys.exit(pytest.main(["-v", "-x", __file__]))