def test_class_registry(self):
"""check if instances are aliased by radiationType().
"""
ltb = ScatteringFactorTable.createByType('LTB')
self.assertTrue(type(ltb) is LocalTable)
ltb2 = ScatteringFactorTable.createByType('localtable')
self.assertTrue(type(ltb2) is LocalTable)
return
def test_class_registry(self):
"""check if instances are aliased by radiationType().
"""
ltb = ScatteringFactorTable.createByType('LTB')
self.assertTrue(type(ltb) is LocalTable)
ltb2 = ScatteringFactorTable.createByType('localtable')
self.assertTrue(type(ltb2) is LocalTable)
return
def fromComposition(cls, composition, sftb, q=0):
"""\
Calculate average scattering factors from atom concentrations.
Parameters
----------
composition : dictionary or a list of (symbol, amount) pairs.
The chemical composition for evaluating the average. Atom
symbols may repeat when it is a list of (symbol, amount) pairs.
sftb : ScatteringFactorTable or str
The ScatteringFactorTable object for looking up the values.
When string use `ScatteringFactorTable.createByType` to create
a new lookup table of the specified type.
q : float or NumPy array (optional)
The Q value in inverse Angstroms for which to lookup
the scattering factor values.
Returns
-------
SFAverage
The calculated scattering factor averages.
"""
from diffpy.srreal.scatteringfactortable import ScatteringFactorTable
sfa = cls()
sfa.composition = {}
if isinstance(composition, dict):
sfa.composition.update(composition)
else:
for smbl, cnt in composition:
if not smbl in sfa.composition:
sfa.composition[smbl] = 0
sfa.composition[smbl] += cnt
sfa.f1sum = 0.0 * q
sfa.f2sum = 0.0 * q
# resolve the lookup table object `tb`
tb = (sftb if not isinstance(sftb, str)
else ScatteringFactorTable.createByType(sftb))
for smbl, cnt in sfa.composition.items():
sfq = tb.lookup(smbl, q)
sfa.f1sum += cnt * sfq
sfa.f2sum += cnt * sfq**2
sfa.count += cnt
denom = sfa.count if sfa.count > 0 else 1
sfa.f1avg = sfa.f1sum / denom
sfa.f2avg = sfa.f2sum / denom
return sfa
def setUp(self):
self.sftx = ScatteringFactorTable.createByType('X')
self.sftn = ScatteringFactorTable.createByType('N')
return
def setUp(self):
self.sftx = ScatteringFactorTable.createByType('X')
self.sftn = ScatteringFactorTable.createByType('N')
return
def setUp(self):
self.sftx = ScatteringFactorTable.createByType('X')
self.sftn = ScatteringFactorTable.createByType('N')
LocalTable()._registerThisType()
return
def setUp(self):
self.sftx = ScatteringFactorTable.createByType('X')
self.sftn = ScatteringFactorTable.createByType('N')
LocalTable()._registerThisType()
return
