AI engineering glossary · Reinforcement learning
What is TD(lambda)?
TD(lambda): A method that blends all n-step returns using weights that decay by a factor lambda between 0 and 1. Lambda = 0 gives one-step updates and lambda = 1 approaches full-run averaging. It is usually implemented efficiently with eligibility traces.
TD(lambda): an example
Lambda = 0.9 is a common middle setting that spreads credit to recent steps while still reducing noise.
Related terms
More Reinforcement learning terms
- Temporal-difference learning
- Terminal state
- Thompson sampling
- Transition probability
- Twin delayed DDPG
- Upper confidence bound
- Value iteration
- World model
Where you learn it
TD(lambda) is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.