Source code for gammapy.irf.psf_3d

# Licensed under a 3-clause BSD style license - see LICENSE.rst
import numpy as np
from astropy import units as u
from astropy.coordinates import Angle
from import fits
from astropy.table import Table
from astropy.utils import lazyproperty
from gammapy.maps import MapAxis
from gammapy.utils.array import array_stats_str
from gammapy.utils.interpolation import ScaledRegularGridInterpolator
from gammapy.utils.scripts import make_path
from .psf_table import EnergyDependentTablePSF, TablePSF

__all__ = ["PSF3D"]

[docs]class PSF3D: """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=u.Quantity(0.1, "TeV"), energy_thresh_hi=u.Quantity(100, "TeV"), interp_kwargs=None, ): self.energy_lo ="TeV") self.energy_hi ="TeV") self.offset = Angle(offset) self.rad_lo = Angle(rad_lo) self.rad_hi = Angle(rad_hi) self.psf_value ="sr^-1") self.energy_thresh_lo ="TeV") self.energy_thresh_hi ="TeV") self._interp_kwargs = interp_kwargs or {} @lazyproperty def _interpolate(self): energy = self._energy_logcenter() offset ="deg") rad = self._rad_center() return ScaledRegularGridInterpolator( points=(rad, offset, energy), values=self.psf_value, **self._interp_kwargs )
[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 """ table =, 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"] = u.Quantity(table.meta["LO_THRES"], "TeV") opts["energy_thresh_hi"] = u.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 : `` 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 = fits.BinTableHDU(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 ``, forwarding all arguments. """ self.to_fits().writeto(filename, *args, **kwargs)
[docs] def evaluate(self, energy=None, offset=None, rad=None): """Interpolate PSF value 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 Returns ------- values : `~astropy.units.Quantity` Interpolated value """ if energy is None: energy = self._energy_logcenter() if offset is None: offset = self.offset if rad is None: rad = self._rad_center() rad = np.atleast_1d(u.Quantity(rad)) offset = np.atleast_1d(u.Quantity(offset)) energy = np.atleast_1d(u.Quantity(energy)) return self._interpolate( ( rad[:, np.newaxis, np.newaxis], offset[np.newaxis, :, np.newaxis], energy[np.newaxis, np.newaxis, :], ) )
[docs] def to_energy_dependent_table_psf(self, theta="0 deg", rad=None, exposure=None): """ Convert PSF3D in EnergyDependentTablePSF. Parameters ---------- theta : `~astropy.coordinates.Angle` Offset in the field of view rad : `~astropy.coordinates.Angle` Offset from PSF center used for evaluating the PSF on a grid. Default is the ``rad`` from this PSF. 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() if rad is None: rad = self._rad_center() else: rad = Angle(rad) psf_value = self.evaluate(offset=theta, rad=rad).squeeze() return EnergyDependentTablePSF( energy=energies, rad=rad, exposure=exposure, psf_value=psf_value.T )
[docs] def to_table_psf(self, energy, theta="0 deg", **kwargs): """Create `~gammapy.irf.TablePSF` at one given energy. Parameters ---------- energy : `~astropy.units.Quantity` Energy theta : `~astropy.coordinates.Angle` Offset in the field of view. Default theta = 0 deg Returns ------- psf : `~gammapy.irf.TablePSF` Table PSF """ energy = u.Quantity(energy) theta = Angle(theta) psf_value = self.evaluate(energy, theta).squeeze() rad = self._rad_center() return TablePSF(rad, psf_value, **kwargs)
[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 = np.atleast_1d(u.Quantity(energy)) theta = np.atleast_1d(u.Quantity(theta)) radii = [] for t in theta: psf = self.to_energy_dependent_table_psf(theta=t) radii.append(psf.containment_radius(energy, fraction=fraction)) return u.Quantity(radii).T.squeeze()
[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 = MapAxis.from_energy_bounds( self.energy_lo[0], self.energy_hi[-1], 100 ).edges for theta in thetas: for fraction in fractions: radius = self.containment_radius(energy, theta, fraction) label = f"{theta.deg} deg, {100 * fraction:.1f}%" 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=u.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(f"Offset ({offset.unit})") ax.set_xlabel(f"Energy ({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 = f"Containment radius R{100 * fraction:.0f} ({containment.unit})" 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 = f"Safe energy threshold: {esafe:3.2f}" 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()