API

Package conway

Top-level package for conway

class conway.FiniteGrid(N=10, boundary='zero', dump=False, load=False, filename='conway')

Naive NxN grid with different boundary conditions. Cells are randomly assigned state (dead or alive).

Parameters

• N (int) – number of cells in the X and Y direction.

• boundary (str) – boundary condition: zero, reflecting, or periodic.

• dump (bool) – pickle the generated FiniteGrid object. (Practical if you discover a nice pattern and you want to view it again.

• load (bool) – if True, load a file with a pickled FiniteGrid object, e.g. to view its evolution again.

• filename (str) – name of the file to be dumped or loaded.

In order to not have to implement special boundary rules, we make the grid (N+2)x(N+2) where the outer layers are ghost cells which are just there to make sure that index i-1, i+1, j-1 and j+1 exist for all cells (i,j):

. | . . . .  | .
--+---------+--
. | 0 0 1 0 | .
. | 0 1 0 0 | .
. | 0 0 1 0 | .
. | 0 1 0 1 | .
--+---------+--
. | . . . . | .

The state of the ghost cells is determined by the boundary conditions:

• all zeros:

  0 | 0 0 0 0 | 0
  --+---------+--
  0 | 0 0 1 0 | 0
  0 | 0 1 0 0 | 0
  0 | 0 0 1 0 | 0
  0 | 0 1 0 1 | 0
  --+---------+--
  0 | 0 0 0 0 | 0
  

• reflective boundary condition: the ghost cell has the same state as the cell on the inside of the boundary:

  0 | 0 0 1 0 | 0
  --+---------+--
  0 | 0 0 1 0 | 0
  0 | 0 1 0 0 | 0
  0 | 0 0 1 0 | 0
  0 | 0 1 0 1 | 1
  --+---------+--
  0 | 0 1 0 1 | 1
  

• Periodic boundary condition: a ghost cell is a copy of the state at the other end, as if the finite grid is repeated in the x and y direction:

  1 | 0 1 0 1 | 0
  --+---------+--
  0 | 0 0 1 0 | 0
  0 | 0 1 0 0 | 0
  0 | 0 0 1 0 | 0
  1 | 0 1 0 1 | 0
  --+---------+--
  0 | 0 0 1 0 | 0
  

apply_0bc()

Apply the zero boundary condition, i.e. surround this FiniteGrid object by zeros.

apply_bc(bc=None)

Apply a boundary condition to this FiniteGrid object.

Parameters

bc (str) – a string identifying the type of boundary condition we want to apply.

apply_pbc()

Apply the periodic boundary condition.

This can be viewed as:

• the square being folded such that opposite ends along each axis are glued together. That first gives a tube and then a torus.

• the square being part of an infinite repetition along each axis yielding a periodic pattern.

apply_rbc()

Apply the reflecting boundary condition, i.e. the surroundig elements have the same value as the value on the inside of the boundary.

curse(stdscr, boundary=True, symbols=None)

‘Print’ the FiniteGrid object to the terminal using the Python curses module.

This gives a nicer visualization because the successive generations are overwriting each other, thus being more close to an animation. The current implementation is limited to the size of the terminal.

Parameters

• stdscr – the curses wrapper object for the terminal.

• boundary (bool) – if True, also prints the surrounding boundary layers.

• symbols (list-like) – use symbols[0] for denoting dead cells, and symbols[1] for denoting living cells in the output. The defaults are `` `` and X.

dump(filename='conway')

Pickle this FiniteGrid object (save to file).

Parameters

filename (str) – name of the pickle file to contain the pickled FiniteGrid object>

evolve(n_generations=1, draw=True, stop_if_static=False, curse=None, interval=0.1)

Let the system evolve over generations generations.

Parameters

• n_generations (int) – the number of generation to evolve.

• draw (bool) – if True, draw each generation on the terminal.

• stop_if_static (bool) – if True stops evolving the system if it is a static state.

• interval (float) – seconds to wait between drawing two successive generations.

static load(filename='conway')

Unpickle a pickled FiniteGrid object.

Parameters

filename (str) – name of the pickle file containing the pickled FiniteGrid object.

Returns

a FiniteGrid object

Raises

RuntimeError if unpickling the file does not yield a FiniteGrid object.

print(boundary=True, symbols=None)

Print this FiniteGrid object to the terminal.

Parameters

• boundary (bool) – if True, also prints the surrounding boundary layers.

• symbols (list-like) – use symbols[0] for denoting dead cells, and symbols[1] for denoting living cells in the output. The defaults are `` `` and X.