Source code for gammapy.irf.psf_3d

# 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()