Matrix Multiplication by Hand ✍️
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Matrix Multiplication by Hand ✍️
Reinforcement Learning with Human Feedback (RLHF) by Hand ✍️
One of the key ingredients of the deep learning revolution is the ability to perform matrix multiplications at incredible speed and scale.
Despite linear algebra being a prerequisite of my courses, I found many students lack confidence in multiplying matrices. So I teach them this unique system for multiplying matrices by hand.
How does it work?
Setup
Step 1 of 9: Given
Multiply A (green, 2×2) by B (yellow, 2×3).
Lay them out compactly: B across the top, A down the left, and an empty grid for the result C where they meet.
Lay Out the Matrices
Step 2 of 9: Place B
Copy B's values across the top.
Step 3 of 9: Place A
Copy A's values down the left.