def _expandElementMassFracs(self):
"""
Expand the custom isotopics input entries that are elementals to isotopics.
This is necessary when the element name is not a elemental nuclide.
Most everywhere else expects Nuclide objects (or nuclide names). This input allows a
user to enter "U" which would expand to the naturally occurring uranium isotopics.
This is different than the isotopic expansion done for meeting user-specified
modeling options (such as an MC**2, or MCNP expecting elements or isotopes),
because it translates the user input into something that can be used later on.
"""
elementsToExpand = []
for nucName in self.massFracs:
if nucName not in nuclideBases.byName:
element = elements.bySymbol.get(nucName)
if element is not None:
runLog.info(
"Expanding custom isotopic `{}` element `{}` to natural isotopics"
.format(self.name, nucName))
# include all natural isotopes with None flag
elementsToExpand.append((element, None))
else:
raise exceptions.InputError(
"Unrecognized nuclide/isotope/element in input: {}".
format(nucName))
densityTools.expandElementalMassFracsToNuclides(
self.massFracs, elementsToExpand)
def _initializeMassFracs(self):
self.massFracs = dict() # defaults to 0.0, __init__ is not called
if any(v < 0.0 for v in self.values()):
raise ValueError(
"Custom isotopic input for {} is negative".format(self.name)
)
valSum = sum(self.values())
if not abs(valSum - 1.0) < 1e-5 and "fractions" in self.inputFormat:
raise ValueError(
"Fractional custom isotopic input values must sum to 1.0 in: {}".format(
self.name
)
)
if self.inputFormat == "number fractions":
sumNjAj = 0.0
for nuc, nj in self.items():
if nj:
sumNjAj += nj * nucDir.getAtomicWeight(nuc)
for nuc, value in self.items():
massFrac = value * nucDir.getAtomicWeight(nuc) / sumNjAj
self.massFracs[nuc] = massFrac
elif self.inputFormat == "number densities":
if self._density is not None:
raise exceptions.InputError(
"Custom isotopic `{}` is over-specified. It was provided as number "
"densities, and but density ({}) was also provided. Is the input format "
"correct?".format(self.name, self.density)
)
M = {
nuc: Ni
/ units.MOLES_PER_CC_TO_ATOMS_PER_BARN_CM
* nucDir.getAtomicWeight(nuc)
for nuc, Ni in self.items()
}
densityTotal = sum(M.values())
if densityTotal < 0:
raise ValueError("Computed density is negative")
for nuc, Mi in M.items():
self.massFracs[nuc] = Mi / densityTotal
self._computedDensity = densityTotal
elif self.inputFormat == "mass fractions":
self.massFracs = dict(self) # as input
else:
raise ValueError(
"Unrecognized custom isotopics input format {}.".format(
self.inputFormat
)
)