openmc.Universe

class openmc.Universe(universe_id=None, name='', cells=None)

A collection of cells that can be repeated.

Parameters:

• universe_id (int, optional) – Unique identifier of the universe. If not specified, an identifier will automatically be assigned
• name (str, optional) – Name of the universe. If not specified, the name is the empty string.
• cells (Iterable of openmc.Cell, optional) – Cells to add to the universe. By default no cells are added.

Variables:

• id (int) – Unique identifier of the universe
• name (str) – Name of the universe
• cells (collections.OrderedDict) – Dictionary whose keys are cell IDs and values are Cell instances

add_cell(cell)

Add a cell to the universe.

Parameters:cell (openmc.Cell) – Cell to add

add_cells(cells)

Add multiple cells to the universe.

Parameters:cells (Iterable of openmc.Cell) – Cells to add

clear_cells()

Remove all cells from the universe.

find(point)

Find cells/universes/lattices which contain a given point

Parameters:point (3-tuple of float) – Cartesian coordinates of the point Returns:Sequence of universes, cells, and lattices which are traversed to find the given point Return type:list

get_all_cells()

Return all cells that are contained within the universe

Returns:cells – Dictionary whose keys are cell IDs and values are Cell instances Return type:collections.OrderedDict

get_all_materials()

Return all materials that are contained within the universe

Returns:materials – Dictionary whose keys are material IDs and values are Material instances Return type:Collections.OrderedDict

get_all_nuclides()

Return all nuclides contained in the universe

Returns:nuclides – Dictionary whose keys are nuclide names and values are 2-tuples of (nuclide, density) Return type:collections.OrderedDict

get_all_universes()

Return all universes that are contained within this one.

Returns:universes – Dictionary whose keys are universe IDs and values are Universe instances Return type:collections.OrderedDict

plot(center=(0.0, 0.0, 0.0), width=(1.0, 1.0), pixels=(200, 200), basis='xy', color_by='cell', colors=None, filename=None, seed=None)

Display a slice plot of the universe.

Parameters:

• center (Iterable of float) – Coordinates at the center of the plot
• width (Iterable of float) – Width of the plot in each basis direction
• pixels (Iterable of int) – Number of pixels to use in each basis direction
• basis ({'xy', 'xz', 'yz'}) – The basis directions for the plot
• color_by ({'cell', 'material'}) – Indicate whether the plot should be colored by cell or by material
• colors (dict) –

  Assigns colors to specific materials or cells. Keys are instances of Cell or Material and values are RGB 3-tuples or RGBA 4-tuples. Red, green, blue, and alpha should all be floats in the range [0.0, 1.0], for example:

  # Make water blue
  water = openmc.Cell(fill=h2o)
  universe.plot(..., colors={water: (0., 0., 1.))
  

• filename (str or None) – Filename to save plot to. If no filename is given, the plot will be displayed using the currently enabled matplotlib backend.
• seed (hashable object or None) – Hashable object which is used to seed the random number generator used to select colors. If None, the generator is seeded from the current time.

remove_cell(cell)

Remove a cell from the universe.

Parameters:cell (openmc.Cell) – Cell to remove