openmc.data.WindowedMultipole

class openmc.data.WindowedMultipole(name)

Resonant cross sections represented in the windowed multipole format.

Parameters:

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

Variables:

• fit_order (Integral) – Order of the windowed curvefit.
• fissionable (bool) – Whether or not the target nuclide has fission data.
• spacing (Real) – 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 (Real) – Square root of the atomic weight ratio of the target nuclide.
• E_min (Real) – Lowest energy in eV the library is valid for.
• E_max (Real) – 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')

Export windowed multipole data to an HDF5 file.

Parameters:

• path (str) – Path to write HDF5 file to
• mode ({'r', 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_hdf5(group_or_filename)

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