flatland.core.grid.rail_env_grid module

class flatland.core.grid.rail_env_grid.RailEnvTransitions

Bases: flatland.core.grid.grid4.Grid4Transitions

Special case of GridTransitions over a 2D-grid, with a pre-defined set of transitions mimicking the types of real Swiss rail connections.

As no diagonal transitions are allowed in the RailEnv environment, the possible transitions for RailEnv from a cell to its neighboring ones are represented over 16 bits.

The 16 bits are organized in 4 blocks of 4 bits each, the direction that the agent is facing. E.g., the most-significant 4-bits represent the possible movements (NESW) if the agent is facing North, etc…

agent’s direction: North East South West agent’s allowed movements: [nesw] [nesw] [nesw] [nesw] example: 1000 0000 0010 0000

In the example, the agent can move from North to South and viceversa.

is_valid(self, cell_transition)

Checks if a cell transition is a valid cell setup.

Parameters:

cell_transition : int

64 bits used to encode the valid transitions for a cell.

Returns:

Boolean

True or False

print(self, cell_transition)

transition_list = [0, 32800, 37408, 33825, 38433, 52275, 20994, 8192, 16386, 4608, 49186]