anomaly_detection_cmsl1t / loader /normalization.py
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# Feature normalisation, fitted on the training split alone.
#
# The scheme is picked by name: 'robust' is what the published studies used, 'standard'
# and 'robust_axov4' are the other two the configuration tree offers, and 'unnormalized'
# leaves the hardware integers as they are.
import logging
import pickle
from dataclasses import dataclass, field
from pathlib import Path
import awkward as ak
import numpy as np
log = logging.getLogger(__name__)
@dataclass
class L1DataNormalizer:
"""Shift and scale each feature of each object by parameters fitted on train.
:param name: The scheme, one of ``unnormalized``, ``robust``, ``standard`` and
``robust_axov4``. It also names the ml-ready cache, so two schemes never share
one directory.
:param hyperparams: Passed to the fit of that scheme, e.g. the quantiles bounding
the robust range. ``None`` for a scheme that takes none.
"""
name: str
hyperparams: dict | None = None
norm_params: dict = field(default_factory=dict, init=False)
def fit(self, data: ak.Array, obj_name: str) -> None:
"""Determine one object's parameters. Fit on the training split only."""
log.info("Fitting %s normalisation to %s.", self.name, obj_name)
self.obj_name = obj_name
fit = getattr(self, f"_{self.name}_fit")
if self.hyperparams:
fit(data, **self.hyperparams)
else:
fit(data)
def norm(self, data: ak.Array, obj_name: str) -> ak.Array:
"""Apply the parameters fitted earlier to any split."""
return getattr(self, f"_{self.name}")(data, obj_name)
def import_norm_params(self, norm_filepath: Path, obj_name: str) -> None:
"""Read one object's parameters back, for a run that did not fit them itself."""
if not Path(norm_filepath).is_file():
raise FileNotFoundError(f"Norm params not found at {norm_filepath}!")
self.norm_params[obj_name] = pickle.loads(Path(norm_filepath).read_bytes())
def export_norm_params(self, norm_filepath: Path, obj_name: str) -> None:
"""Write one object's parameters beside the split they were fitted on."""
if Path(norm_filepath).suffix != ".pkl":
raise ValueError(
f"Norm params are only written to .pkl, not {norm_filepath}."
)
Path(norm_filepath).write_bytes(pickle.dumps(self.norm_params[obj_name]))
def setup_1d_denorm(self, object_feature_map: dict) -> None:
"""Build the tensors that undo the normalisation on a flattened model input.
:param object_feature_map: ``{object: {feature: [flat indices]}}``, as the torch
stage writes it beside the tensors.
"""
import torch
self.object_feature_map = object_feature_map
length = sum(len(i) for m in object_feature_map.values() for i in m.values())
self.scale_tensor = torch.ones(length, dtype=torch.float32)
self.shift_tensor = torch.zeros(length, dtype=torch.float32)
for obj_name, feature_map in object_feature_map.items():
self._fill_1d(obj_name, feature_map)
def norm_1d_tensor(self, data):
"""Normalise a flattened model input in place."""
scale, shift = self._as(data)
return data.sub_(shift).div_(scale)
def denorm_1d_tensor(self, data):
"""Undo :meth:`norm_1d_tensor` in place, e.g. on a model's reconstruction."""
scale, shift = self._as(data)
return data.mul_(scale).add_(shift)
def _fill_1d(self, obj_name: str, feature_map: dict) -> None:
"""One object's parameters, spread over the columns it occupies."""
params = self.norm_params.get(obj_name)
if not params:
raise ValueError(f"Missing norm params for the {obj_name} object.")
for feat, idxs in feature_map.items():
self.scale_tensor[idxs] = float(params.get(feat, {}).get("scale", 1.0))
self.shift_tensor[idxs] = float(params.get(feat, {}).get("shift", 0.0))
def _as(self, data):
"""The parameter tensors, on the device and dtype of the data they act on."""
if getattr(self, "scale_tensor", None) is None:
raise ValueError("Run setup_1d_denorm before normalising a flat tensor.")
return (
self.scale_tensor.to(device=data.device, dtype=data.dtype),
self.shift_tensor.to(device=data.device, dtype=data.dtype),
)
def _affine(self, data: ak.Array, obj_name: str) -> ak.Array:
"""Shift and scale every feature by the parameters fitted for it."""
params = self.norm_params[obj_name]
return ak.Array(
{
f: (data[f] - params[f]["shift"]) / params[f]["scale"]
for f in data.fields
}
)
def _unnormalized(self, data: ak.Array, obj_name: str) -> ak.Array:
return data
def _unnormalized_fit(self, data: ak.Array) -> None:
self._record({f: (0.0, 1.0) for f in data.fields})
# Three schemes that differ in how they are fitted and not in how they are applied.
_robust = _affine
_standard = _affine
_robust_axov4 = _affine
def _robust_fit(self, data: ak.Array, percentiles: list) -> None:
"""Shift by the median, scale by the interquantile range."""
fitted = {}
for feat in data.fields:
values = _values(data[feat])
low, high = np.quantile(values, percentiles)
fitted[feat] = (float(np.median(values)), float(high - low))
self._record(fitted)
def _standard_fit(self, data: ak.Array) -> None:
"""Shift by the mean, scale by the standard deviation."""
fitted = {}
for feat in data.fields:
values = _values(data[feat])
fitted[feat] = (float(np.mean(values)), float(np.std(values)))
self._record(fitted)
def _robust_axov4_fit(self, data: ak.Array, percentiles: list, scale: list) -> None:
"""Robust, with the quantile range mapped onto the interval ``scale``.
``scale = [2, -2]`` puts the quantile range between -2 and 2 rather than between
0 and 1, which is the convention the axol1tl v4 and v5 trainings were run with.
"""
width = scale[0] - scale[1]
fitted = {}
for feat in data.fields:
low, high = np.quantile(_values(data[feat]), percentiles)
fitted[feat] = (
(low * scale[0] - high * scale[1]) / width,
(high - low) / width,
)
self._record(fitted)
def _record(self, fitted: dict) -> None:
"""Store one object's parameters, guarding the degenerate scale of a flat feature."""
self.norm_params[self.obj_name] = {
feat: {"shift": shift, "scale": scale if scale else 1e-12}
for feat, (shift, scale) in fitted.items()
}
def _values(feature: ak.Array) -> np.ndarray:
"""One feature's real entries, the padding not yet being there to exclude."""
return ak.to_numpy(ak.flatten(feature))