07. Matrix Multiplication: Part 2

Important Reminders About Matrix Multiplication

• The number of columns in the left matrix must equal the number of rows in the right matrix.
• The answer matrix always has the same number of rows as the left matrix and the same number of columns as the right matrix.
• Order matters. Multiplying A•B is not the same as multiplying B•A.
• Data in the left matrix should be arranged as rows., while data in the right matrix should be arranged as columns.

If you keep these four points in mind, you should always be able to figure out how to properly arrange your matrix multiplications when building a neural network.