def make_rsp(self, wave):
'''Interpolate the COS LSF for all wavelengths
Parameters
----------
wave : ndarray
wavelength (assumed to be in Ang)
'''
# test if delta_lambda in wavelengths is as expected for this grating
for disp in self.disp:
if max(abs(np.diff(wave) - disp)) < (disp / 100.):
break
else:
print('LSF convolution requires x to be binned in pixels.')
print('delta(x) differs from value given in COS IHB.')
# first line of table is header values
wavelen = self.lsf_tab[0, 1:]
if ((min(wave) < 0.9 * min(wavelen)) or (max(wave) > 1.1 * max(wavelen))):
raise ValueError('COS LSF in this model is only tabulated {0:4.0f} to {1:0.0f}'.format(min(wavelen), max(wavelen)))
# rest of table is data values
# 1. Interpolation: Get lsf_tab on pixel grid
# interpolate to full pixels, if given in fractional pixels
lsftab = np.zeros((self.m, len(wavelen)))
for i in range(len(wavelen)):
lsftab[:,i] = interpolate(np.arange(-(self.m/2), self.m/2+0.1, dtype = np.int), self.shift, self.lsf_tab[1:,i+1])
# 2. Interpolation: make lsf for each lambda
n = len(wave)
self._rsp = np.zeros((n, self.m))
for i in np.arange(-(self.m/2), self.m/2+0.1, dtype = np.int):
pix = interpolate(wave, wavelen, lsftab[self.m/2+i,:])
self._rsp[:, self.m/2 + i] = pix
if np.isfinite(self._rsp).sum() != self._rsp.size:
raise ValueError('Response matrix holds nan or inf values!')
# 3. Reformat: Bring matix in same shape as Sherpa would do for RMFs
# I use the same naming convention here as in Sherpa `DataRMF` objects
self._grp = np.ones(n)
self._fch = np.clip(np.arange(1,n+1)-(self.m/2),1, np.inf)
# set unused matix elements to nan - that allows a very simple
# way to flatten the array
for i in range(self.m/2):
self._rsp[i,0:self.m/2-i] = np.nan
self._rsp[-(i+1),-(self.m/2)+i:self.m] = np.nan
self._nch = np.sum(np.isfinite(self._rsp),axis = 1)
self._rsp = self._rsp[np.isfinite(self._rsp)].flatten()
self.cache_x = wave
def _evaluate(self, data_space, pars, modelfunc, **kwargs):
# Evaluate the model on the user-defined grid and then interpolate/rebin
# onto the desired grid. This is based on sherpa.models.TableModel
# but is simplified as we do not provide a fold method.
kwargs[
'integrate'] = self.integrate # Not really sure I need this, but let's be safe
evaluation_space = self.evaluation_space
if not data_space in evaluation_space:
warnings.warn(
"evaluation space does not contain the requested space. Sherpa will join the two spaces."
)
evaluation_space = evaluation_space.join(data_space)
# I don't like the string of IFs, but it might be more expressive this way in this specific case.
# If the data space is integrated and the model's integrate flag is set to True, then evaluate the model
# on the evaluation space and then rebin onto the data space.
# If the data space is integrated but the model's integrate flas is set to False, then evaluate the model
# on the midpoint grid (note: we are passing the midpoint grid to force Sherpa to treat this as not integrated.
# If we passed two arrays we'd fall in a edge case and Sherpa would evaluate the model at the edge of the bin.
# If the data space is not integrated then simply evaluate the model on the grid and then interpolate
# to match the data space.
if data_space.is_integrated:
if self.integrate:
# This should be the most common case
y = modelfunc(pars, evaluation_space.grid[0],
evaluation_space.grid[1], **kwargs)
return rebin(y, evaluation_space.grid[0],
evaluation_space.grid[1], data_space.grid[0],
data_space.grid[1])
else:
# The integrate flag is set to false, so just evaluate the model
# and then interpolate using the grids midpoints.
y = modelfunc(pars, evaluation_space.midpoint_grid, **kwargs)
return interpolate(data_space.midpoint_grid,
evaluation_space.midpoint_grid,
y,
function=self.method)
else:
y = modelfunc(pars, evaluation_space.grid[0], **kwargs)
return interpolate(data_space.midpoint_grid,
evaluation_space.midpoint_grid,
y,
function=self.method)
def calc(self, pl, pr, rhs, *args, **kwargs):
args = list(args) # tuples are immutable!
# add m/2 elements to the wavelength array on each side
# to avoid edge effects when folding with the LSF
args[0] = interpolate(np.arange(-(self.m/2), len(args[0]) + self.m/2-0.1), np.arange(len(args[0])), args[0])
flux = rhs(pr, *args, **kwargs)
return self.convolve(args[0], flux)[self.m/2 : -(self.m/2)]
def _evaluate(self, data_space, pars, modelfunc, **kwargs):
# Evaluate the model on the user-defined grid and then interpolate/rebin
# onto the desired grid. This is based on sherpa.models.TableModel
# but is simplified as we do not provide a fold method.
kwargs['integrate'] = self.integrate # Not really sure I need this, but let's be safe
evaluation_space = self.evaluation_space
if not data_space in evaluation_space:
warnings.warn("evaluation space does not contain the requested space. Sherpa will join the two spaces.")
evaluation_space = evaluation_space.join(data_space)
# I don't like the string of IFs, but it might be more expressive this way in this specific case.
# If the data space is integrated and the model's integrate flag is set to True, then evaluate the model
# on the evaluation space and then rebin onto the data space.
# If the data space is integrated but the model's integrate flas is set to False, then evaluate the model
# on the midpoint grid (note: we are passing the midpoint grid to force Sherpa to treat this as not integrated.
# If we passed two arrays we'd fall in a edge case and Sherpa would evaluate the model at the edge of the bin.
# If the data space is not integrated then simply evaluate the model on the grid and then interpolate
# to match the data space.
if data_space.is_integrated:
if self.integrate:
# This should be the most common case
y = modelfunc(pars, evaluation_space.grid[0], evaluation_space.grid[1],
**kwargs)
return rebin(y,
evaluation_space.grid[0], evaluation_space.grid[1],
data_space.grid[0], data_space.grid[1])
else:
# The integrate flag is set to false, so just evaluate the model
# and then interpolate using the grids midpoints.
y = modelfunc(pars, evaluation_space.midpoint_grid, **kwargs)
return interpolate(data_space.midpoint_grid, evaluation_space.midpoint_grid, y,
function=self.method)
else:
y = modelfunc(pars, evaluation_space.grid, **kwargs)
return interpolate(data_space.midpoint_grid, evaluation_space.midpoint_grid, y,
function=self.method)
def _estimate_expmap(self, *args):
"""Estimate the exposure map given an ARF.
Although the arguments are listed with parameter names
below, the function **does not** accept named arguments.
It uses positional arguments and type checks to determine
the parameters.
Parameters
----------
crate
A TABLECrate, containing ``energ_lo``, ``energ_hi``,
and ``specresp`` columns.
filename : string
The name of an ARF file
xlo, xhi, y : arrays of numbers
The arrays taken to be the ``energ_lo``, ``energ_hi``, and
``specresp`` columns
Return
------
expmap : number
An estimate of the exposure map at the position
of the source, and has units of cm^2 count / self.fluxtype
Notes
-----
The ARF is linearly interpolated onto the energy grid
of the dataset and the weighted sum calculated. The
ARF is assumed to have units of cm^2 count / photon, and
be defined on a grid given in keV.
The ``estimate_instmap()`` method should be called in
preference to this routine.
"""
nargs = len(args)
if nargs == 3:
elo = args[0]
ehi = args[1]
specresp = args[2]
if len(elo) == 1 or len(ehi) == 1 or len(specresp) == 1:
emsg = "Expected three arrays of the same " + \
"length, with more than one element in"
raise TypeError(emsg)
if len(elo) != len(ehi) or len(elo) != len(specresp):
emsg = "Expected three arrays of the same length"
raise ValueError(emsg)
elif nargs != 1:
emsg = "_estimate_expmap() takes 2 or 4 arguments " + \
"({} given)".format(nargs + 1)
raise TypeError(emsg)
else:
if isinstance(args[0], pycrates.TABLECrate):
cr = args[0]
else:
cr = pycrates.TABLECrate(args[0], mode="r")
try:
elo = cr.get_column("ENERG_LO").values.copy()
ehi = cr.get_column("ENERG_HI").values.copy()
specresp = cr.get_column("SPECRESP").values.copy()
except ValueError as e:
fname = cr.get_filename()
raise ValueError("Crate {} - {}".format(fname, e))
# Interpolate using the mid-point of the ARF
# onto the mid-point of the grid if necessary.
#
emid = 0.5 * (elo + ehi)
if emid.shape == self.xmid.shape and \
np.all(emid == self.xmid):
arf = specresp
else:
arf = su.interpolate(self.xmid, emid, specresp)
arf = np.asarray(arf, dtype=self.weight.dtype)
arf[arf < 0] = 0.0
return np.sum(self.weight * arf)
