def test_arf1d_no_pha_no_exposure_call(exposure):
"Can we call an ARF (no PHA)"
egrid = np.arange(0.1, 0.6, 0.1)
specresp = np.asarray([1.1, 1.2, 1.3, 1.4])
adata = create_arf(egrid[:-1], egrid[1:], specresp, exposure=exposure)
arf = ARF1D(adata)
mdl = Const1D('flat')
mdl.c0 = 2.3
wrapped = arf(mdl)
assert isinstance(wrapped, ARFModelNoPHA)
wmdl = wrapped.model
if exposure is None:
assert wmdl == mdl
else:
# It looks like equality is not well defined for the model
# classes, since the following assertion fails
# assert wmdl == (exposure * mdl)
# so manually check
#
assert isinstance(wmdl, BinaryOpModel)
assert wmdl.op == np.multiply
assert wmdl.rhs == mdl
assert isinstance(wmdl.lhs, ArithmeticConstantModel)
assert wmdl.lhs.val == pytest.approx(exposure)
def test_arf1d_no_pha_zero_energy_bin_replace():
"What happens when the first bin starts at 0, with replacement"
ethresh = 1e-5
exposure = 0.1
egrid = np.asarray([0.0, 0.1, 0.2, 0.4, 0.5, 0.7, 0.8])
elo = egrid[:-1]
ehi = egrid[1:]
specresp = np.asarray([10.2, 9.8, 10.0, 12.0, 8.0, 10.0])
with warnings.catch_warnings(record=True) as ws:
warnings.simplefilter("always")
adata = create_arf(elo,
ehi,
specresp,
exposure=exposure,
ethresh=ethresh)
validate_zero_replacement(ws, 'ARF', 'user-arf', ethresh)
arf = ARF1D(adata)
mdl = MyPowLaw1D()
tmdl = PowLaw1D()
wrapped = arf(mdl)
out = wrapped([0.1, 0.2])
elo[0] = ethresh
expected = exposure * specresp * tmdl(elo, ehi)
assert_allclose(out, expected)
assert not np.isnan(out[0])
def derive_identity_arf(name, arf):
"""Create an "identity" ARF that has uniform sensitivity.
*name*
The name of the ARF object to be created; passed to Sherpa.
*arf*
An existing ARF object on which to base this one.
Returns:
A new ARF1D object that has a uniform spectral response vector.
In many X-ray observations, the relevant background signal does not behave
like an astrophysical source that is filtered through the telescope's
response functions. However, I have been unable to get current Sherpa
(version 4.9) to behave how I want when working with backround models that
are *not* filtered through these response functions. This function
constructs an "identity" ARF response function that has uniform sensitivity
as a function of detector channel.
"""
from sherpa.astro.data import DataARF
from sherpa.astro.instrument import ARF1D
darf = DataARF(
name,
arf.energ_lo,
arf.energ_hi,
np.ones(arf.specresp.shape),
arf.bin_lo,
arf.bin_hi,
arf.exposure,
header=None,
)
return ARF1D(darf, pha=arf._pha)
def test_arf1d_empty():
arf = ARF1D(None)
assert arf._arf is None
assert arf._pha is None
assert str(arf) == str(None)
# Since there's no ARF to fall through, it should be an error
# to access the name attribute.
#
with pytest.raises(AttributeError):
arf.name
def test_arf1d_pha_zero_energy_bin():
"What happens when the first bin starts at 0, with replacement"
ethresh = 1.0e-10
# Note: the two exposures are different to check which is
# used (the answer is neither, which seems surprising)
#
exposure1 = 0.1
egrid = np.asarray([0.0, 0.1, 0.2, 0.4, 0.5, 0.7, 0.8])
elo = egrid[:-1]
ehi = egrid[1:]
specresp = np.asarray([10.2, 9.8, 10.0, 12.0, 8.0, 10.0])
with warnings.catch_warnings(record=True) as ws:
warnings.simplefilter("always")
adata = create_arf(elo,
ehi,
specresp,
exposure=exposure1,
ethresh=ethresh)
validate_zero_replacement(ws, 'ARF', 'user-arf', ethresh)
arf = ARF1D(adata)
exposure2 = 2.4
channels = np.arange(1, 7, dtype=np.int16)
counts = np.ones(6, dtype=np.int16)
pha = DataPHA('test-pha',
channel=channels,
counts=counts,
exposure=exposure2)
pha.set_arf(adata)
pha.set_analysis('energy')
mdl = MyPowLaw1D()
tmdl = PowLaw1D()
wrapped = ARFModelPHA(arf, pha, mdl)
out = wrapped([0.1, 0.2])
elo[0] = ethresh
expected = specresp * tmdl(elo, ehi)
assert_allclose(out, expected)
assert not np.isnan(out[0])
def test_arf1d_no_pha_no_exposure_basic():
"Can we create an ARF with no PHA?"
egrid = np.arange(0.1, 0.6, 0.1)
adata = create_arf(egrid[:-1], egrid[1:])
arf = ARF1D(adata)
assert arf._arf == adata
assert arf._pha is None
# Does the ARF1D pass through functionality to the DataARF?
assert arf.name == 'user-arf'
assert arf.exposure is None
assert str(arf) == str(adata)
assert dir(arf) == dir(adata)
# Should be exact
specresp = np.ones(egrid.size - 1, dtype=np.float32)
assert (specresp == arf.specresp).all()
