# Licensed under a 3-clause BSD style license - see LICENSE.rst
from __future__ import absolute_import, division, print_function, unicode_literals
import numpy as np
from astropy.table import Table
from astropy.io import fits
from astropy.units import Quantity
from astropy.coordinates import Angle
from ..utils.array import array_stats_str
from ..utils.fits import table_to_fits_table
from ..utils.energy import Energy
from ..utils.scripts import make_path
from .psf_table import TablePSF, EnergyDependentTablePSF
__all__ = [
'PSF3D',
]
[docs]class PSF3D(object):
"""PSF with axes: energy, offset, rad.
Data format specification: :ref:`gadf:psf_table`
Parameters
----------
energy_lo : `~astropy.units.Quantity`
Energy bins lower edges (1-dim)
energy_hi : `~astropy.units.Quantity`
Energy bins upper edges (1-dim)
offset : `~astropy.coordinates.Angle`
Offset angle (1-dim)
rad_lo : `~astropy.coordinates.Angle`
Offset angle bins lower edges
rad_hi : `~astropy.coordinates.Angle`
Offset angle bins upper edges
psf_value : `~astropy.units.Quantity`
PSF (3-dim with axes: psf[rad_index, offset_index, energy_index]
energy_thresh_lo : `~astropy.units.Quantity`
Lower energy threshold.
energy_thresh_hi : `~astropy.units.Quantity`
Upper energy threshold.
"""
def __init__(self, energy_lo, energy_hi, offset, rad_lo, rad_hi, psf_value,
energy_thresh_lo=Quantity(0.1, 'TeV'),
energy_thresh_hi=Quantity(100, 'TeV')):
self.energy_lo = energy_lo.to('TeV')
self.energy_hi = energy_hi.to('TeV')
self.offset = Angle(offset)
self.rad_lo = Angle(rad_lo)
self.rad_hi = Angle(rad_hi)
self.psf_value = psf_value.to('sr^-1')
self.energy_thresh_lo = energy_thresh_lo.to('TeV')
self.energy_thresh_hi = energy_thresh_hi.to('TeV')
[docs] def info(self):
"""Print some basic info.
"""
ss = "\nSummary PSF3D info\n"
ss += "---------------------\n"
ss += array_stats_str(self.energy_lo, 'energy_lo')
ss += array_stats_str(self.energy_hi, 'energy_hi')
ss += array_stats_str(self.offset, 'offset')
ss += array_stats_str(self.rad_lo, 'rad_lo')
ss += array_stats_str(self.rad_hi, 'rad_hi')
ss += array_stats_str(self.psf_value, 'psf_value')
# TODO: should quote containment values also
return ss
def _energy_logcenter(self):
"""Get logcenters of energy bins.
Returns
-------
energies : `~astropy.units.Quantity`
Logcenters of energy bins
"""
return np.sqrt(self.energy_lo * self.energy_hi)
def _rad_center(self):
"""Get centers of rad bins (`~astropy.coordinates.Angle` in deg).
"""
return ((self.rad_hi + self.rad_lo) / 2).to('deg')
[docs] @classmethod
def read(cls, filename, hdu='PSF_2D_TABLE'):
"""Create `PSF3D` from FITS file.
Parameters
----------
filename : str
File name
hdu : str
HDU name
"""
filename = str(make_path(filename))
table = Table.read(filename, hdu=hdu)
return cls.from_table(table)
[docs] @classmethod
def from_table(cls, table):
"""Create `PSF3D` from `~astropy.table.Table`.
Parameters
----------
table : `~astropy.table.Table`
Table Table-PSF info.
"""
theta_lo = table['THETA_LO'].quantity[0]
theta_hi = table['THETA_HI'].quantity[0]
offset = (theta_hi + theta_lo) / 2
offset = Angle(offset, unit=table['THETA_LO'].unit)
energy_lo = table['ENERG_LO'].quantity[0]
energy_hi = table['ENERG_HI'].quantity[0]
rad_lo = table['RAD_LO'].quantity[0]
rad_hi = table['RAD_HI'].quantity[0]
psf_value = table['RPSF'].quantity[0]
opts = {}
try:
opts['energy_thresh_lo'] = Quantity(table.meta['LO_THRES'], 'TeV')
opts['energy_thresh_hi'] = Quantity(table.meta['HI_THRES'], 'TeV')
except KeyError:
pass
return cls(energy_lo, energy_hi, offset, rad_lo, rad_hi, psf_value, **opts)
[docs] def to_fits(self):
"""
Convert PSF table data to FITS HDU list.
Returns
-------
hdu_list : `~astropy.io.fits.HDUList`
PSF in HDU list format.
"""
# Set up data
names = ['ENERG_LO', 'ENERG_HI', 'THETA_LO', 'THETA_HI',
'RAD_LO', 'RAD_HI', 'RPSF']
units = ['TeV', 'TeV', 'deg', 'deg',
'deg', 'deg', 'sr^-1']
data = [self.energy_lo, self.energy_hi, self.offset, self.offset,
self.rad_lo, self.rad_hi, self.psf_value]
table = Table()
for name_, data_, unit_ in zip(names, data, units):
table[name_] = [data_]
table[name_].unit = unit_
hdu = table_to_fits_table(table)
hdu.header['LO_THRES'] = self.energy_thresh_lo.value
hdu.header['HI_THRES'] = self.energy_thresh_hi.value
return fits.HDUList([fits.PrimaryHDU(), hdu])
[docs] def write(self, filename, *args, **kwargs):
"""Write PSF to FITS file.
Calls `~astropy.io.fits.HDUList.writeto`, forwarding all arguments.
"""
self.to_fits().writeto(filename, *args, **kwargs)
[docs] def evaluate(self, energy=None, offset=None, rad=None,
interp_kwargs=None):
"""Interpolate the value of the `EnergyOffsetArray` at a given offset and energy.
Parameters
----------
energy : `~astropy.units.Quantity`
energy value
offset : `~astropy.coordinates.Angle`
Offset in the field of view
rad : `~astropy.coordinates.Angle`
Offset wrt source position
interp_kwargs : dict
option for interpolation for `~scipy.interpolate.RegularGridInterpolator`
Returns
-------
values : `~astropy.units.Quantity`
Interpolated value
"""
from scipy.interpolate import RegularGridInterpolator
if not interp_kwargs:
interp_kwargs = dict(bounds_error=False, fill_value=None)
if energy is None:
energy = self._energy_logcenter()
if offset is None:
offset = self.offset
if rad is None:
rad = self._rad_center()
energy = Energy(energy).to('TeV')
offset = Angle(offset).to('deg')
rad = Angle(rad).to('deg')
energy_bin = self._energy_logcenter()
offset_bin = self.offset.to('deg')
rad_bin = self._rad_center()
points = (rad_bin, offset_bin, energy_bin)
interpolator = RegularGridInterpolator(points, self.psf_value, **interp_kwargs)
rr, off, ee = np.meshgrid(rad.value, offset.value, energy.value, indexing='ij')
shape = ee.shape
pix_coords = np.column_stack([rr.flat, off.flat, ee.flat])
data_interp = interpolator(pix_coords)
return Quantity(data_interp.reshape(shape), self.psf_value.unit)
[docs] def to_energy_dependent_table_psf(self, theta='0 deg', exposure=None):
"""
Convert PSF3D in EnergyDependentTablePSF.
Parameters
----------
theta : `~astropy.coordinates.Angle`
Offset in the field of view
exposure : `~astropy.units.Quantity`
Energy dependent exposure. Should be in units equivalent to 'cm^2 s'.
Default exposure = 1.
Returns
-------
table_psf : `~gammapy.irf.EnergyDependentTablePSF`
Energy-dependent PSF
"""
theta = Angle(theta)
energies = self._energy_logcenter()
rad = self._rad_center()
psf_value = self.evaluate(offset=theta)
psf_value = psf_value[:, 0, :].transpose()
return EnergyDependentTablePSF(
energy=energies, rad=rad,
exposure=exposure, psf_value=psf_value,
)
[docs] def to_table_psf(self, energy, theta='0 deg', interp_kwargs=None, **kwargs):
"""Evaluate the `EnergyOffsetArray` at one given energy.
Parameters
----------
energy : `~astropy.units.Quantity`
Energy
theta : `~astropy.coordinates.Angle`
Offset in the field of view. Default theta = 0 deg
interp_kwargs : dict
Option for interpolation for `~scipy.interpolate.RegularGridInterpolator`
Returns
-------
table : `~astropy.table.Table`
Table with two columns: offset, value
"""
energy = Quantity(energy)
theta = Angle(theta)
psf_value = self.evaluate(energy, theta, interp_kwargs=interp_kwargs).squeeze()
rad = self._rad_center()
table_psf = TablePSF(rad, psf_value, **kwargs)
return table_psf
[docs] def containment_radius(self, energy, theta='0 deg', fraction=0.68, interp_kwargs=None):
"""Containment radius.
Parameters
----------
energy : `~astropy.units.Quantity`
Energy
theta : `~astropy.coordinates.Angle`
Offset in the field of view. Default theta = 0 deg
fraction : float
Containment fraction. Default fraction = 0.68
Returns
-------
radius : `~astropy.units.Quantity`
Containment radius in deg
"""
energy = Quantity(energy)
if energy.ndim == 0:
energy = Quantity([energy.value], energy.unit)
theta = Angle(theta)
if theta.ndim == 0:
theta = Quantity([theta.value], theta.unit)
unit = None
radius = np.zeros((energy.size, theta.size))
for e in range(energy.size):
for t in range(theta.size):
try:
psf = self.to_table_psf(energy[e], theta[t], interp_kwargs)
except:
# This can raise an `error` from scipy UnivariateSpline:
# error: (xb<=x[0]) failed for 2nd keyword xb: fpcurf0:xb=nan
# Not sure what type exactly or how to catch it.
radius[e, t] = np.nan
continue
r = psf.containment_radius(fraction)
radius[e, t] = r.value
unit = r.unit
return Quantity(radius.squeeze(), unit)
[docs] def plot_containment_vs_energy(self, fractions=[0.68, 0.95],
thetas=Angle([0, 1], 'deg'), ax=None):
"""Plot containment fraction as a function of energy.
"""
import matplotlib.pyplot as plt
ax = plt.gca() if ax is None else ax
energy = Energy.equal_log_spacing(
self.energy_lo[0], self.energy_hi[-1], 100)
for theta in thetas:
for fraction in fractions:
radius = self.containment_radius(energy, theta, fraction).squeeze()
label = '{} deg, {:.1f}%'.format(theta, 100 * fraction)
ax.plot(energy.value, radius.value, label=label)
ax.semilogx()
ax.legend(loc='best')
ax.set_xlabel('Energy (TeV)')
ax.set_ylabel('Containment radius (deg)')
[docs] def plot_psf_vs_rad(self, theta='0 deg', energy=Quantity(1, 'TeV')):
"""Plot PSF vs rad.
Parameters
----------
energy : `~astropy.units.Quantity`
Energy. Default energy = 1 TeV
theta : `~astropy.coordinates.Angle`
Offset in the field of view. Default theta = 0 deg
"""
theta = Angle(theta)
table = self.to_table_psf(energy=energy, theta=theta)
return table.plot_psf_vs_rad()
[docs] def plot_containment(self, fraction=0.68, ax=None, show_safe_energy=False,
add_cbar=True, **kwargs):
"""
Plot containment image with energy and theta axes.
Parameters
----------
fraction : float
Containment fraction between 0 and 1.
add_cbar : bool
Add a colorbar
"""
import matplotlib.pyplot as plt
ax = plt.gca() if ax is None else ax
energy = self._energy_logcenter()
offset = self.offset
# Set up and compute data
containment = self.containment_radius(energy, offset, fraction)
# plotting defaults
kwargs.setdefault('cmap', 'GnBu')
kwargs.setdefault('vmin', np.nanmin(containment.value))
kwargs.setdefault('vmax', np.nanmax(containment.value))
# Plotting
x = energy.value
y = offset.value
caxes = ax.pcolormesh(x, y, containment.value.T, **kwargs)
# Axes labels and ticks, colobar
ax.semilogx()
ax.set_ylabel('Offset ({unit})'.format(unit=offset.unit))
ax.set_xlabel('Energy ({unit})'.format(unit=energy.unit))
ax.set_xlim(x.min(), x.max())
ax.set_ylim(y.min(), y.max())
if show_safe_energy:
self._plot_safe_energy_range(ax)
if add_cbar:
label = ('Containment radius R{0:.0f} ({1})'
''.format(100 * fraction, containment.unit))
cbar = ax.figure.colorbar(caxes, ax=ax, label=label)
return ax
def _plot_safe_energy_range(self, ax):
"""add safe energy range lines to the plot"""
esafe = self.energy_thresh_lo
omin = self.offset.value.min()
omax = self.offset.value.max()
ax.hlines(y=esafe.value, xmin=omin, xmax=omax)
label = 'Safe energy threshold: {0:3.2f}'.format(esafe)
ax.text(x=0.1, y=0.9 * esafe.value, s=label, va='top')
[docs] def peek(self, figsize=(15, 5)):
"""Quick-look summary plots."""
import matplotlib.pyplot as plt
fig, axes = plt.subplots(nrows=1, ncols=3, figsize=figsize)
self.plot_containment(fraction=0.68, ax=axes[0])
self.plot_containment(fraction=0.95, ax=axes[1])
self.plot_containment_vs_energy(ax=axes[2])
# TODO: implement this plot
# psf = self.psf_at_energy_and_theta(energy='1 TeV', theta='1 deg')
# psf.plot_components(ax=axes[2])
plt.tight_layout()