# Smoothing & perplexity

Subject: Natural Language Processing

Exam: M2

Reader: https://deep-learning-study-room.vercel.app/nlp/#m2/formulas/f-smoothing

Canonical: https://deep-learning-study-room.vercel.app/read/nlp/m2/formulas-chapter/f-smoothing/

Formulas explained through full worked examples

1. [Laplace smoothing: why both numerator and denominator change](https://deep-learning-study-room.vercel.app/read/nlp/m2/formulas/f-smoothing--laplace-basics/)
2. [A complete unseen-bigram question from corpus to final answer](https://deep-learning-study-room.vercel.app/read/nlp/m2/formulas/f-smoothing--smoothed-sentence/)
3. [Adjusted counts and relative discounting](https://deep-learning-study-room.vercel.app/read/nlp/m2/formulas/f-smoothing--adjusted-count-discount/)
4. [Perplexity: meaning, formula and four complete examples](https://deep-learning-study-room.vercel.app/read/nlp/m2/formulas/f-smoothing--evaluation-perplexity/)
5. [Log probabilities: replace long products with sums](https://deep-learning-study-room.vercel.app/read/nlp/m2/formulas/f-smoothing--log-probabilities/)