Function compute_nstep_returns 

pub fn compute_nstep_returns(
    buffer: &mut RolloutBuffer,
    last_values: &[f32],
    gamma: f32,
)

Compute n-step returns (simpler alternative to GAE)

This computes un-discounted n-step returns without advantage normalization. Useful for debugging or when GAE is not needed.

Arguments

• buffer - Rollout buffer to compute returns for
• last_values - Value estimates for final states [num_envs]
• gamma - Discount factor