# Licensed under a 3-clause BSD style license - see LICENSE.rst
import logging
import numpy as np
import astropy.units as u
from gammapy.data import GTI
from gammapy.datasets import Datasets
from gammapy.maps import LabelMapAxis, Map, TimeMapAxis
from gammapy.utils.pbar import progress_bar
from .core import FluxPoints
from .sed import FluxPointsEstimator
__all__ = ["LightCurveEstimator"]
log = logging.getLogger(__name__)
[docs]class LightCurveEstimator(FluxPointsEstimator):
"""Estimate light curve.
The estimator will apply flux point estimation on the source model component to datasets
in each of the provided time intervals. The normalization is the only
parameter of the source model left free to vary. Other model components
can be left free to vary with the reoptimize option.
If no time intervals are provided, the estimator will use the time intervals
defined by the datasets GTIs.
To be included in the estimation, the dataset must have their GTI fully
overlapping a time interval.
Time intervals without any dataset GTI fully overlapping will be dropped. They will not
be stored in the final lightcurve `FluxPoints` object.
Parameters
----------
time_intervals : list of `astropy.time.Time`
Start and stop time for each interval to compute the LC
source : str or int
For which source in the model to compute the flux points. Default is 0
energy_edges : `~astropy.units.Quantity`
Energy edges of the light curve.
atol : `~astropy.units.Quantity`
Tolerance value for time comparison with different scale. Default 1e-6 sec.
norm_min : float
Minimum value for the norm used for the fit statistic profile evaluation.
norm_max : float
Maximum value for the norm used for the fit statistic profile evaluation.
norm_n_values : int
Number of norm values used for the fit statistic profile.
norm_values : `numpy.ndarray`
Array of norm values to be used for the fit statistic profile.
n_sigma : int
Number of sigma to use for asymmetric error computation. Default is 1.
n_sigma_ul : int
Number of sigma to use for upper limit computation. Default is 2.
selection_optional : list of str
Which steps to execute. Available options are:
* "all": all the optional steps are executed
* "errn-errp": estimate asymmetric errors.
* "ul": estimate upper limits.
* "scan": estimate fit statistic profiles.
Default is None so the optional steps are not executed.
fit : `Fit`
Fit instance specifying the backend and fit options.
reoptimize : bool
Re-optimize other free model parameters. Default is True.
Examples
--------
For a usage example see :doc:`/tutorials/analysis-time/light_curve` tutorial.
"""
tag = "LightCurveEstimator"
def __init__(self, time_intervals=None, atol="1e-6 s", **kwargs):
self.time_intervals = time_intervals
self.atol = u.Quantity(atol)
super().__init__(**kwargs)
[docs] def run(self, datasets):
"""Run light curve extraction.
Normalize integral and energy flux between emin and emax.
Parameters
----------
datasets : list of `~gammapy.datasets.SpectrumDataset` or `~gammapy.datasets.MapDataset`
Spectrum or Map datasets.
Returns
-------
lightcurve : `~gammapy.estimators.FluxPoints`
Light curve flux points
"""
datasets = Datasets(datasets)
if self.time_intervals is None:
gti = datasets.gti
else:
gti = GTI.from_time_intervals(self.time_intervals)
gti = gti.union(overlap_ok=False, merge_equal=False)
rows = []
valid_intervals = []
for t_min, t_max in progress_bar(gti.time_intervals, desc="Time intervals"):
datasets_to_fit = datasets.select_time(
time_min=t_min, time_max=t_max, atol=self.atol
)
if len(datasets_to_fit) == 0:
log.info(
f"No Dataset for the time interval {t_min} to {t_max}. Skipping interval."
)
continue
valid_intervals.append([t_min, t_max])
fp = self.estimate_time_bin_flux(datasets=datasets_to_fit)
for name in ["counts", "npred", "npred_excess"]:
fp._data[name] = self.expand_map(
fp._data[name], dataset_names=datasets.names
)
rows.append(fp)
if len(rows) == 0:
raise ValueError("LightCurveEstimator: No datasets in time intervals")
gti = GTI.from_time_intervals(valid_intervals)
axis = TimeMapAxis.from_gti(gti=gti)
return FluxPoints.from_stack(
maps=rows,
axis=axis,
)
[docs] @staticmethod
def expand_map(m, dataset_names):
"""Expand map in dataset axis
Parameters
----------
map : `Map`
Map to expand.
dataset_names : list of str
Dataset names
Returns
-------
map : `Map`
Expanded map.
"""
label_axis = LabelMapAxis(labels=dataset_names, name="dataset")
geom = m.geom.replace_axis(axis=label_axis)
result = Map.from_geom(geom, data=np.nan)
coords = m.geom.get_coord(sparse=True)
result.set_by_coord(coords, vals=m.data)
return result
[docs] def estimate_time_bin_flux(self, datasets):
"""Estimate flux point for a single energy group.
Parameters
----------
datasets : `~gammapy.modeling.Datasets`
List of dataset objects
Returns
-------
result : `FluxPoints`
Resulting flux points.
"""
return super().run(datasets)