加载和写入数据¶

from snowflake.ml.data.data_connector import DataConnector
from snowflake.snowpark.context import get_active_session

session = get_active_session()

# Create DataConnector from a Snowflake table
data_connector = DataConnector.from_dataframe(session.table("example-table-name"))

from snowflake.ml.data.data_connector import DataConnector

# Create DataConnector from a Snowflake Dataset
data_connector = DataConnector.from_dataset(snowflake_dataset)

from snowflake.ml.data.data_connector import DataConnector
from snowflake.ml.modeling.distributors.xgboost.xgboost_estimator import (
    XGBEstimator,
    XGBScalingConfig,
)
from snowflake.snowpark.context import get_active_session

session = get_active_session()

# Create DataConnector from a Snowpark dataframe
snowflake_df = session.table("TRAINING_TABLE")
data_connector = DataConnector.from_dataframe(snowflake_df)

# Create Snowflake XGBoost estimator
snowflake_est = XGBEstimator(
    n_estimators=1,
    objective="reg:squarederror",
    scaling_config=XGBScalingConfig(use_gpu=False),
)

# Train using the data connector
# When using a data connector, input_cols and label_col must be provided
fit_booster = snowflake_est.fit(
    data_connector,
    input_cols=NUMERICAL_COLS,
    label_col=LABEL_COL
)

from sklearn import datasets
from snowflake.ml.data.sharded_data_connector import ShardedDataConnector
from snowflake.ml.modeling.pytorch import (
    PyTorchTrainer,
    ScalingConfig,
    WorkerResourceConfig,
    getContext,
)
from torch import nn
from snowflake.snowpark.context import get_active_session

session = get_active_session()

# Create the Snowflake data from a Snowpark dataframe
digits = datasets.load_digits(as_frame=True).frame
digits_df = session.create_dataframe(digits)

# Create sharded data connector
sharded_data_connector = ShardedDataConnector.from_dataframe(digits_df)

# Define the PyTorch model
class DigitsModel(nn.Module):
    def __init__(self):
        super(DigitsModel, self).__init__()
        self.flatten = nn.Flatten()
        self.linear_relu_stack = nn.Sequential(
            nn.Linear(8 * 8, 512),
            nn.ReLU(),
            nn.Linear(512, 512),
            nn.ReLU(),
            nn.Linear(512, 10)
        )

    def forward(self, x):
        x = self.flatten(x)
        logits = self.linear_relu_stack(x)
        return logits

# Define training function that runs across multiple nodes or devices
# Each process receives a unique data shard
def train_func():
    import os
    import torch
    import torch.distributed as dist
    from torch.utils.data import DataLoader
    from torch import nn
    from torch.nn.parallel import DistributedDataParallel as DDP

    # Get context with data shards and model directory
    context = getContext()
    dataset_map = context.get_dataset_map()
    model_dir = context.get_model_dir()
    training_data = dataset_map["train"].get_shard().to_torch_dataset()
    train_dataloader = DataLoader(training_data, batch_size=batch_size, drop_last=True)

    dist.init_process_group()
    device = "cpu"
    label_col = '"target"'
    batch_size = 64

    model = DDP(DigitsModel())
    loss_fn = nn.CrossEntropyLoss()
    optimizer = torch.optim.SGD(model.parameters(), lr=1e-3)

    # Training loop
    for epoch in range(5):
        for batch, batch_data in enumerate(train_dataloader):
            y = batch_data.pop(label_col).flatten().type(torch.LongTensor).to(device)
            X = torch.concat(
                [tensor.to(torch.float32) for tensor in batch_data.values()],
                dim=-1,
            ).to(device)
            pred = model(X)
            loss = loss_fn(pred, y)

            optimizer.zero_grad()
            loss.backward()
            optimizer.step()

            if batch % 100 == 0:
                print(f"Epoch {epoch}, Batch {batch}, Loss: {loss.item()}")

    # Save the model
    if dist.get_rank() == 0:
        torch.save(model.state_dict(), os.path.join(model_dir, "digits_model.pth"))

# Create PyTorch trainer with scaling configuration
pytorch_trainer = PyTorchTrainer(
    train_func=train_func,
    scaling_config=ScalingConfig(
        num_nodes=1,
        num_workers_per_node=4,
        resource_requirements_per_worker=WorkerResourceConfig(num_cpus=1, num_gpus=0),
    ),
)

# Run distributed training
response = pytorch_trainer.run(
    dataset_map=dict(
        train=sharded_data_connector,
    )
)

import ray
from snowflake.ml.ray.datasource.stage_parquet_file_datasource import SFStageParquetDataSource
from snowflake.ml.data.data_connector import DataConnector

data_source = SFStageParquetDataSource(
    stage_location="@stage/path/",
    database="DB_NAME", # optional
    schema="SCHEMA_NAME", # optional
    file_pattern='*.parquet', # optional
)

# Build Ray dataset from provided datasources
ray_ds = ray.data.read_datasource(data_source)

dc = DataConnector.from_ray_dataset(ray_ds)