Is there an example of action masking for continuous actions?

I have the following.

obs_space = spaces.Box(low=-1000,high=1000, shape=(30x50,))

act_space = spaces.Box(low=-0.05,high=0.05, shape=(30x3,))

so the 30 X 50 matrix actually is 20 X 50 and I pad the rest 10 X 50 with zeros. After that, I flatten it to get (1500,) dimension observations.

I want to add an action mask such that the model produces actions for 20 X 3 and the rest actions i.e. 10 X 3 are zero.

I am using PPO and ray2.0.0

How do I do this?

Thnx for your help in advance.