def test_lsf_errors():
"""
Test that LSF raises errors correctly
"""
with pytest.raises(RuntimeError):
LSF()
with pytest.raises(RuntimeError):
LSF(filename='NOTAFILE.txt')
def test_gaussian_lsf():
"""
Create an LSF object with a gaussian function and assure it works OK
"""
lsf = LSF(function='gaussian', width=5)
assert isinstance(lsf.kernel, astropy.convolution.kernels.Gaussian1DKernel)
assert len(lsf.kernel.array) == 41
assert lsf.width == 5
print(lsf)
def test_boxcar_lsf():
"""
Create an LSF object with a boxcar function and assure it works OK
"""
lsf = LSF(function='boxcar', width=5)
assert isinstance(lsf.kernel, np.ndarray)
assert len(lsf.kernel) == 5
assert lsf.width == 5
print(lsf)
def test_lsf_from_filename():
"""
Create an LSF object from filename and assure that it works OK
"""
lsf = LSF(filename='avg_COS.txt')
assert isinstance(lsf.kernel, np.ndarray)
assert len(lsf.kernel) > 0
assert lsf.width == len(lsf.kernel)
print(lsf)
def apply_lsf(self, function=None, width=None, filename=None):
"""
Postprocess a spectrum to apply a line spread function.
If the SpectrumGenerator already has an LSF_kernel set, it will
be used when no keywords are supplied. Otherwise, the user can
specify a filename of a user-defined kernel or a function+width
for a kernel. Valid functions are: "boxcar" and "gaussian".
For more information, see :class:`~trident.LSF` and
:class:`~trident.Instrument`.
**Parameters**
:function: string, optional
Desired functional form for the applied LSF kernel.
Valid options are currently "boxcar" or "gaussian"
Default: None
:width: int, optional
Width of the desired LSF kernel in bin elements
Default: None
:filename: string, optional
The filename of the user-supplied kernel for applying the LSF
Default: None
**Example**
Make a one zone ray and generate a COS spectrum for it. Apply the
COS line spread function to it.
>>> import trident
>>> ray = trident.make_onezone_ray()
>>> sg = trident.SpectrumGenerator('COS')
>>> sg.make_spectrum(ray)
>>> sg.apply_lsf()
>>> sg.plot_spectrum('spec_lsf_corrected.png')
Make a one zone ray and generate a spectrum with bin width = 1 angstrom.
Apply a boxcar LSF to it with width 50 angstroms.
>>> import trident
>>> ray = trident.make_onezone_ray()
>>> sg = trident.SpectrumGenerator(lambda_min=1100, lambda_max=1200, dlambda=1)
>>> sg.make_spectrum(ray)
>>> sg.apply_lsf(function='boxcar', width=50)
>>> sg.plot_spectrum('spec_lsf_corrected.png')
"""
# if nothing is specified, then use the Instrument-defined kernel
if function is None and width is None and filename is None:
if self.instrument.lsf_kernel is None:
raise RuntimeError("To apply a line spread function, you "
"must specify one or use an instrument "
"where one is defined.")
else:
mylog.info("Applying default line spread function for %s." % \
self.instrument.name)
lsf = LSF(filename=self.instrument.lsf_kernel)
else:
mylog.info("Applying specified line spread function.")
lsf = LSF(function=function, width=width, filename=filename)
from astropy.convolution import convolve
self.flux_field = convolve(self.flux_field, lsf.kernel)
# Negative fluxes don't make sense, so clip
np.clip(self.flux_field, 0, np.inf, out=self.flux_field)