Fehu_envs.Mountain_carSourceMountain car with sparse reward (MountainCar-v0).
A car sits in a valley between two hills. The engine is too weak to climb the right hill directly; the agent must build momentum by rocking back and forth. Reward is -1.0 per step. The episode terminates when the car reaches position >= 0.5 with non-negative velocity, and truncates at 200 steps.
Observation: Fehu.Space.spec.Box of shape [2] -- position, velocity.
Actions: Fehu.Space.spec.Discrete 3 -- 0 = push left, 1 = coast, 2 = push right.
Render modes: ansi.
make () is a mountain car environment.