openmc.data.WindowedMultipole

class openmc.data.WindowedMultipole(name)[source]

Resonant cross sections represented in the windowed multipole format.

Parameters

name (str) – Name of the nuclide using the GNDS naming convention

Variables
  • name (str) – Name of the nuclide using the GNDS naming convention

  • spacing (float) – The width of each window in sqrt(E)-space. For example, the frst window will end at (sqrt(E_min) + spacing)**2 and the second window at (sqrt(E_min) + 2*spacing)**2.

  • sqrtAWR (float) – Square root of the atomic weight ratio of the target nuclide.

  • E_min (float) – Lowest energy in eV the library is valid for.

  • E_max (float) – Highest energy in eV the library is valid for.

  • data (np.ndarray) – A 2D array of complex poles and residues. data[i, 0] gives the energy at which pole i is located. data[i, 1:] gives the residues associated with the i-th pole. There are 3 residues, one each for the scattering, absorption, and fission channels.

  • windows (np.ndarray) – A 2D array of Integral values. windows[i, 0] - 1 is the index of the first pole in window i. windows[i, 1] - 1 is the index of the last pole in window i.

  • broaden_poly (np.ndarray) – A 1D array of boolean values indicating whether or not the polynomial curvefit in that window should be Doppler broadened.

  • curvefit (np.ndarray) – A 3D array of Real curvefit polynomial coefficients. curvefit[i, 0, :] gives coefficients for the scattering cross section in window i. curvefit[i, 1, :] gives absorption coefficients and curvefit[i, 2, :] gives fission coefficients. The polynomial terms are increasing powers of sqrt(E) starting with 1/E e.g: a/E + b/sqrt(E) + c + d sqrt(E) + …

export_to_hdf5(path, mode='a', libver='earliest')[source]

Export windowed multipole data to an HDF5 file.

Parameters
  • path (str) – Path to write HDF5 file to

  • mode ({'r+', 'w', 'x', 'a'}) – Mode that is used to open the HDF5 file. This is the second argument to the h5py.File constructor.

  • libver ({'earliest', 'latest'}) – Compatibility mode for the HDF5 file. ‘latest’ will produce files that are less backwards compatible but have performance benefits.

classmethod from_endf(endf_file, log=False, vf_options=None, wmp_options=None)[source]

Generate windowed multipole neutron data from an ENDF evaluation.

New in version 0.12.1.

Parameters
  • endf_file (str) – Path to ENDF evaluation

  • log (bool or int, optional) – Whether to print running logs (use int for verbosity control)

  • vf_options (dict, optional) – Dictionary of keyword arguments, e.g. {‘njoy_error’: 0.001}, passed to openmc.data.multipole.vectfit_nuclide()

  • wmp_options (dict, optional) – Dictionary of keyword arguments, e.g. {‘search’: True, ‘rtol’: 0.01}, passed to openmc.data.WindowedMultipole.from_multipole()

Returns

Resonant cross sections represented in the windowed multipole format.

Return type

openmc.data.WindowedMultipole

classmethod from_hdf5(group_or_filename)[source]

Construct a WindowedMultipole object from an HDF5 group or file.

Parameters

group_or_filename (h5py.Group or str) – HDF5 group containing multipole data. If given as a string, it is assumed to be the filename for the HDF5 file, and the first group is used to read from.

Returns

Resonant cross sections represented in the windowed multipole format.

Return type

openmc.data.WindowedMultipole

classmethod from_multipole(mp_data, search=None, log=False, **kwargs)[source]

Generate windowed multipole neutron data from multipole data.

Parameters
  • mp_data (dictionary or str) – Dictionary or Path to the multipole data stored in a pickle file

  • search (bool, optional) – Whether to search for optimal window size and curvefit order. Defaults to True if no windowing parameters are specified.

  • log (bool or int, optional) – Whether to print running logs (use int for verbosity control)

  • **kwargs – Keyword arguments passed to openmc.data.multipole._windowing()

Returns

Resonant cross sections represented in the windowed multipole format.

Return type

openmc.data.WindowedMultipole