Before revision:  First, the agent's action space is modeled as a combinatorial action space of trading directions with prespecified trading sizes for each asset . Second, we introduce a mapping function that can replace an initially-determined action that may be infeasible with a feasible action that is reasonably close to the original, ideal action.
After revision:  First, the agent's action space is modeled as a combinatorial action space of trading directions with prespecified trading sizes for each asset . Second, we introduce a mapping function that can replace an initially-determined action that may be infeasible with a feasible action closest to the originally proposed ideal action.