from collections.abc import Mapping
from ctypes import c_int, c_double, c_char_p, POINTER, c_size_t
from weakref import WeakValueDictionary
from numpy.ctypeslib import ndpointer
import numpy as np
from ..exceptions import DataError, AllocationError
from . import _dll
from .core import _FortranObject
from .error import _error_handler
__all__ = ['Nuclide', 'nuclides', 'load_nuclide']
_array_1d_dble = ndpointer(dtype=np.double, ndim=1, flags='CONTIGUOUS')
# Nuclide functions
_dll.openmc_get_nuclide_index.argtypes = [c_char_p, POINTER(c_int)]
_dll.openmc_get_nuclide_index.restype = c_int
_dll.openmc_get_nuclide_index.errcheck = _error_handler
_dll.openmc_load_nuclide.argtypes = [c_char_p, POINTER(c_double), c_int]
_dll.openmc_load_nuclide.restype = c_int
_dll.openmc_load_nuclide.errcheck = _error_handler
_dll.openmc_nuclide_name.argtypes = [c_int, POINTER(c_char_p)]
_dll.openmc_nuclide_name.restype = c_int
_dll.openmc_nuclide_name.errcheck = _error_handler
_dll.openmc_nuclide_collapse_rate.argtypes = [c_int, c_int, c_double,
_array_1d_dble, _array_1d_dble, c_int, POINTER(c_double)]
_dll.openmc_nuclide_collapse_rate.restype = c_int
_dll.openmc_nuclide_collapse_rate.errcheck = _error_handler
_dll.nuclides_size.restype = c_size_t
[docs]def load_nuclide(name):
"""Load cross section data for a nuclide.
Parameters
----------
name : str
Name of the nuclide, e.g. 'U235'
"""
_dll.openmc_load_nuclide(name.encode(), None, 0)
[docs]class Nuclide(_FortranObject):
"""Nuclide stored internally.
This class exposes a nuclide that is stored internally in the OpenMC
solver. To obtain a view of a nuclide with a given name, use the
:data:`openmc.lib.nuclides` mapping.
Parameters
----------
index : int
Index in the `nuclides` array.
Attributes
----------
name : str
Name of the nuclide, e.g. 'U235'
"""
__instances = WeakValueDictionary()
def __new__(cls, *args):
if args not in cls.__instances:
instance = super().__new__(cls)
cls.__instances[args] = instance
return cls.__instances[args]
def __init__(self, index):
self._index = index
@property
def name(self):
name = c_char_p()
_dll.openmc_nuclide_name(self._index, name)
return name.value.decode()
[docs] def collapse_rate(self, MT, temperature, energy, flux):
"""Calculate reaction rate based on group-wise flux distribution
Parameters
----------
MT : int
ENDF MT value of the desired reaction
temperature : float
Temperature in [K] at which to evaluate cross sections
energy : iterable of float
Energy group boundaries in [eV]
flux : iterable of float
Flux in each energt group (not normalized per eV)
Returns
-------
float
Reaction rate
"""
energy = np.asarray(energy, dtype=float)
flux = np.asarray(flux, dtype=float)
xs = c_double()
_dll.openmc_nuclide_collapse_rate(self._index, MT, temperature, energy,
flux, len(flux), xs)
return xs.value
class _NuclideMapping(Mapping):
"""Provide mapping from nuclide name to index in nuclides array."""
def __getitem__(self, key):
index = c_int()
try:
_dll.openmc_get_nuclide_index(key.encode(), index)
except (DataError, AllocationError) as e:
# __contains__ expects a KeyError to work correctly
raise KeyError(str(e))
return Nuclide(index.value)
def __iter__(self):
for i in range(len(self)):
yield Nuclide(i).name
def __len__(self):
return _dll.nuclides_size()
def __repr__(self):
return repr(dict(self))
nuclides = _NuclideMapping()