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2026-07-13 13:17:40 +08:00

140 lines
4.7 KiB
Python

from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Union
import numpy as np
import pyarrow
import tensorflow as tf
from ray.data._internal.tensor_extensions.arrow import get_arrow_extension_tensor_types
from ray.data.util.data_batch_conversion import _unwrap_ndarray_object_type_if_needed
if TYPE_CHECKING:
from ray.data._internal.pandas_block import PandasBlockSchema
def convert_ndarray_to_tf_tensor(
ndarray: np.ndarray,
dtype: Optional[tf.dtypes.DType] = None,
type_spec: Optional[tf.TypeSpec] = None,
) -> tf.Tensor:
"""Convert a NumPy ndarray to a TensorFlow Tensor.
Args:
ndarray: A NumPy ndarray that we wish to convert to a TensorFlow Tensor.
dtype: A TensorFlow dtype for the created tensor; if None, the dtype will be
inferred from the NumPy ndarray data.
type_spec: A type spec that specifies the shape and dtype of the returned
tensor. If you specify ``dtype``, the dtype stored in the type spec is
ignored.
Returns:
A TensorFlow Tensor.
"""
if dtype is None and type_spec is not None:
dtype = type_spec.dtype
is_ragged = isinstance(type_spec, tf.RaggedTensorSpec)
ndarray = _unwrap_ndarray_object_type_if_needed(ndarray)
if is_ragged:
return tf.ragged.constant(ndarray, dtype=dtype)
else:
return tf.convert_to_tensor(ndarray, dtype=dtype)
def convert_ndarray_batch_to_tf_tensor_batch(
ndarrays: Union[np.ndarray, Dict[str, np.ndarray]],
dtypes: Optional[Union[tf.dtypes.DType, Dict[str, tf.dtypes.DType]]] = None,
) -> Union[tf.Tensor, Dict[str, tf.Tensor]]:
"""Convert a NumPy ndarray batch to a TensorFlow Tensor batch.
Args:
ndarrays: A (dict of) NumPy ndarray(s) that we wish to convert to a TensorFlow
Tensor.
dtypes: A (dict of) TensorFlow dtype(s) for the created tensor; if None, the
dtype will be inferred from the NumPy ndarray data.
Returns:
A (dict of) TensorFlow Tensor(s).
"""
if isinstance(ndarrays, np.ndarray):
# Single-tensor case.
if isinstance(dtypes, dict):
if len(dtypes) != 1:
raise ValueError(
"When constructing a single-tensor batch, only a single dtype "
f"should be given, instead got: {dtypes}"
)
dtypes = next(iter(dtypes.values()))
batch = convert_ndarray_to_tf_tensor(ndarrays, dtypes)
else:
# Multi-tensor case.
batch = {
col_name: convert_ndarray_to_tf_tensor(
col_ndarray,
dtype=dtypes[col_name] if isinstance(dtypes, dict) else dtypes,
)
for col_name, col_ndarray in ndarrays.items()
}
return batch
def get_type_spec(
schema: Union["pyarrow.lib.Schema", "PandasBlockSchema"],
columns: Union[str, List[str]],
) -> Union[tf.TypeSpec, Dict[str, tf.TypeSpec]]:
import pyarrow as pa
from ray.data.extensions import TensorDtype
tensor_extension_types = get_arrow_extension_tensor_types()
assert not isinstance(schema, type)
dtypes: Dict[str, Union[np.dtype, pa.DataType]] = dict(
zip(schema.names, schema.types)
)
def get_dtype(dtype: Union[np.dtype, pa.DataType]) -> tf.dtypes.DType:
if isinstance(dtype, pa.ListType):
dtype = dtype.value_type
if isinstance(dtype, pa.DataType):
dtype = dtype.to_pandas_dtype()
if isinstance(dtype, TensorDtype):
dtype = dtype.element_dtype
res = tf.dtypes.as_dtype(dtype)
return res
def get_shape(dtype: Union[np.dtype, pa.DataType]) -> Tuple[int, ...]:
shape = (None,)
if isinstance(dtype, tensor_extension_types):
dtype = dtype.to_pandas_dtype()
if isinstance(dtype, pa.ListType):
shape += (None,)
elif isinstance(dtype, TensorDtype):
shape += dtype.element_shape
return shape
def get_tensor_spec(
dtype: Union[np.dtype, pa.DataType], *, name: str
) -> tf.TypeSpec:
shape, dtype = get_shape(dtype), get_dtype(dtype)
# Batch dimension is always `None`. So, if there's more than one `None`-valued
# dimension, then the tensor is ragged.
is_ragged = sum(dim is None for dim in shape) > 1
if is_ragged:
type_spec = tf.RaggedTensorSpec(shape, dtype=dtype)
else:
type_spec = tf.TensorSpec(shape, dtype=dtype, name=name)
return type_spec
if isinstance(columns, str):
name, dtype = columns, dtypes[columns]
return get_tensor_spec(dtype, name=name)
return {
name: get_tensor_spec(dtype, name=name)
for name, dtype in dtypes.items()
if name in columns
}