WeichenXu f4628c22a4
[pyspark] Implement SparkXGBRanker estimator (#8172)
Signed-off-by: Weichen Xu <weichen.xu@databricks.com>
2022-08-23 02:35:19 +08:00

257 lines
8.6 KiB
Python

"""Utilities for processing spark partitions."""
from collections import defaultdict, namedtuple
from typing import Any, Callable, Dict, Iterator, List, Optional, Sequence, Tuple
import numpy as np
import pandas as pd
from scipy.sparse import csr_matrix
from xgboost.compat import concat
from xgboost import DataIter, DeviceQuantileDMatrix, DMatrix
def stack_series(series: pd.Series) -> np.ndarray:
"""Stack a series of arrays."""
array = series.to_numpy(copy=False)
array = np.stack(array)
return array
# Global constant for defining column alias shared between estimator and data
# processing procedures.
Alias = namedtuple("Alias", ("data", "label", "weight", "margin", "valid", "qid"))
alias = Alias("values", "label", "weight", "baseMargin", "validationIndicator", "qid")
def concat_or_none(seq: Optional[Sequence[np.ndarray]]) -> Optional[np.ndarray]:
"""Concatenate the data if it's not None."""
if seq:
return concat(seq)
return None
def cache_partitions(
iterator: Iterator[pd.DataFrame], append: Callable[[pd.DataFrame, str, bool], None]
) -> None:
"""Extract partitions from pyspark iterator. `append` is a user defined function for
accepting new partition."""
def make_blob(part: pd.DataFrame, is_valid: bool) -> None:
append(part, alias.data, is_valid)
append(part, alias.label, is_valid)
append(part, alias.weight, is_valid)
append(part, alias.margin, is_valid)
append(part, alias.qid, is_valid)
has_validation: Optional[bool] = None
for part in iterator:
if has_validation is None:
has_validation = alias.valid in part.columns
if has_validation is True:
assert alias.valid in part.columns
if has_validation:
train = part.loc[~part[alias.valid], :]
valid = part.loc[part[alias.valid], :]
else:
train, valid = part, None
make_blob(train, False)
if valid is not None:
make_blob(valid, True)
class PartIter(DataIter):
"""Iterator for creating Quantile DMatrix from partitions."""
def __init__(self, data: Dict[str, List], device_id: Optional[int]) -> None:
self._iter = 0
self._device_id = device_id
self._data = data
super().__init__()
def _fetch(self, data: Optional[Sequence[pd.DataFrame]]) -> Optional[pd.DataFrame]:
if not data:
return None
if self._device_id is not None:
import cudf # pylint: disable=import-error
import cupy as cp # pylint: disable=import-error
# We must set the device after import cudf, which will change the device id to 0
# See https://github.com/rapidsai/cudf/issues/11386
cp.cuda.runtime.setDevice(self._device_id)
return cudf.DataFrame(data[self._iter])
return data[self._iter]
def next(self, input_data: Callable) -> int:
if self._iter == len(self._data[alias.data]):
return 0
input_data(
data=self._fetch(self._data[alias.data]),
label=self._fetch(self._data.get(alias.label, None)),
weight=self._fetch(self._data.get(alias.weight, None)),
base_margin=self._fetch(self._data.get(alias.margin, None)),
qid=self._fetch(self._data.get(alias.qid, None)),
)
self._iter += 1
return 1
def reset(self) -> None:
self._iter = 0
def _read_csr_matrix_from_unwrapped_spark_vec(part: pd.DataFrame) -> csr_matrix:
# variables for constructing csr_matrix
csr_indices_list, csr_indptr_list, csr_values_list = [], [0], []
n_features = 0
for vec_type, vec_size_, vec_indices, vec_values in zip(
part.featureVectorType,
part.featureVectorSize,
part.featureVectorIndices,
part.featureVectorValues,
):
if vec_type == 0:
# sparse vector
vec_size = int(vec_size_)
csr_indices = vec_indices
csr_values = vec_values
else:
# dense vector
# Note: According to spark ML VectorUDT format,
# when type field is 1, the size field is also empty.
# we need to check the values field to get vector length.
vec_size = len(vec_values)
csr_indices = np.arange(vec_size, dtype=np.int32)
csr_values = vec_values
if n_features == 0:
n_features = vec_size
assert n_features == vec_size
csr_indices_list.append(csr_indices)
csr_indptr_list.append(csr_indptr_list[-1] + len(csr_indices))
csr_values_list.append(csr_values)
csr_indptr_arr = np.array(csr_indptr_list)
csr_indices_arr = np.concatenate(csr_indices_list)
csr_values_arr = np.concatenate(csr_values_list)
return csr_matrix(
(csr_values_arr, csr_indices_arr, csr_indptr_arr), shape=(len(part), n_features)
)
def create_dmatrix_from_partitions(
iterator: Iterator[pd.DataFrame],
feature_cols: Optional[Sequence[str]],
gpu_id: Optional[int],
kwargs: Dict[str, Any], # use dict to make sure this parameter is passed.
enable_sparse_data_optim: bool,
) -> Tuple[DMatrix, Optional[DMatrix]]:
"""Create DMatrix from spark data partitions. This is not particularly efficient as
we need to convert the pandas series format to numpy then concatenate all the data.
Parameters
----------
iterator :
Pyspark partition iterator.
kwargs :
Metainfo for DMatrix.
"""
# pylint: disable=too-many-locals, too-many-statements
train_data: Dict[str, List[np.ndarray]] = defaultdict(list)
valid_data: Dict[str, List[np.ndarray]] = defaultdict(list)
n_features: int = 0
def append_m(part: pd.DataFrame, name: str, is_valid: bool) -> None:
nonlocal n_features
if name in part.columns:
array = part[name]
if name == alias.data:
array = stack_series(array)
if n_features == 0:
n_features = array.shape[1]
assert n_features == array.shape[1]
if is_valid:
valid_data[name].append(array)
else:
train_data[name].append(array)
def append_m_sparse(part: pd.DataFrame, name: str, is_valid: bool) -> None:
nonlocal n_features
if name == alias.data or name in part.columns:
if name == alias.data:
array = _read_csr_matrix_from_unwrapped_spark_vec(part)
if n_features == 0:
n_features = array.shape[1]
assert n_features == array.shape[1]
else:
array = part[name]
if is_valid:
valid_data[name].append(array)
else:
train_data[name].append(array)
def append_dqm(part: pd.DataFrame, name: str, is_valid: bool) -> None:
"""Preprocessing for DeviceQuantileDMatrix"""
nonlocal n_features
if name == alias.data or name in part.columns:
if name == alias.data:
cname = feature_cols
else:
cname = name
array = part[cname]
if name == alias.data:
if n_features == 0:
n_features = array.shape[1]
assert n_features == array.shape[1]
if is_valid:
valid_data[name].append(array)
else:
train_data[name].append(array)
def make(values: Dict[str, List[np.ndarray]], kwargs: Dict[str, Any]) -> DMatrix:
data = concat_or_none(values[alias.data])
label = concat_or_none(values.get(alias.label, None))
weight = concat_or_none(values.get(alias.weight, None))
margin = concat_or_none(values.get(alias.margin, None))
qid = concat_or_none(values.get(alias.qid, None))
return DMatrix(
data=data, label=label, weight=weight, base_margin=margin, qid=qid, **kwargs
)
is_dmatrix = feature_cols is None
if is_dmatrix:
if enable_sparse_data_optim:
append_fn = append_m_sparse
assert "missing" in kwargs and kwargs["missing"] == 0.0
else:
append_fn = append_m
cache_partitions(iterator, append_fn)
dtrain = make(train_data, kwargs)
else:
cache_partitions(iterator, append_dqm)
it = PartIter(train_data, gpu_id)
dtrain = DeviceQuantileDMatrix(it, **kwargs)
dvalid = make(valid_data, kwargs) if len(valid_data) != 0 else None
assert dtrain.num_col() == n_features
if dvalid is not None:
assert dvalid.num_col() == dtrain.num_col()
return dtrain, dvalid