AI Anatomy Class · Part 1 · AI speaks in numbers

8. Close means similar

Q. Can numbers help you find a friend with a taste like yours?

1. Let's keep only the tips of last chapter's arrows. Each dot is one friend's taste.
2. Two dots close together mean similar tastes. You can measure the distance with the Pythagorean theorem from middle school.
3. Mia and Emma differ by 1 across and 1 up: the distance is √2, about 1.4. Mia and Noah: about 8.5. Emma is much closer.
4. With more friends, the dots form groups: Team Spicy and Team Sweet. Close dots gather together.
5. AI finds similar things the same way. Song recommendations and similar-photo search both come down to finding close points.
6. Words can be dots too. Words with similar meanings sit close: fruits with fruits, pets with pets. More in chapter 33.
7. Close means similar. Next, we learn the dot product, which measures similarity by direction instead of distance.

Chapter summary

• When the tips of two vectors are close, they are similar.
• Distance by the Pythagorean theorem: √(across difference² + up difference²).
• Similar things gather. Recommendations and word meanings are both "find the close point".