matrix_multiply_anim.py

# Using manim community edition

from manim import *

config.frame_width = 22

text1 = MathTex(r"\begin{bmatrix} 3 & 9 & 5 \\ 9 & 4 & 2 \\ 7 & 3 & 6 \end{bmatrix} \begin{bmatrix} 5 & 7 & 2 & 4 \\ 3 & 6 & 9 & 8 \\ 2 & 7 & 1 & 4 \end{bmatrix}")

text2 = MathTex(r"\begin{bmatrix} 3 & 9 & 5 \\ 9 & 4 & 2 \\ 7 & 3 & 6 \end{bmatrix} \begin{bmatrix} 5 & 7 & 2 & 4 \\ 3 & 6 & 9 & 8 \\ 2 & 7 & 1 & 4 \end{bmatrix}", r"&=", r"\begin{bmatrix} 3 \\ 9 \\ 7 \end{bmatrix} \begin{bmatrix} 5 & 7 & 2 & 4 \end{bmatrix} + \begin{bmatrix} 9 \\ 4 \\ 3 \end{bmatrix} \begin{bmatrix} 3 & 6 & 9 & 8 \end{bmatrix} + \begin{bmatrix} 5 \\ 2 \\ 6 \end{bmatrix} \begin{bmatrix} 2 & 7 & 1 & 4 \end{bmatrix} \\")

text3 = MathTex(r"\begin{bmatrix} 3 & 9 & 5 \\ 9 & 4 & 2 \\ 7 & 3 & 6 \end{bmatrix} \begin{bmatrix} 5 & 7 & 2 & 4 \\ 3 & 6 & 9 & 8 \\ 2 & 7 & 1 & 4 \end{bmatrix}", r"&=", r"\begin{bmatrix} 15 & 21 & 6 & 12 \\ 45 & 63 & 18 & 36 \\ 35 & 49 & 14 & 28 \end{bmatrix} + \begin{bmatrix} 27 & 54 & 81 & 72 \\ 12 & 24 & 36 & 32 \\ 9 & 18 & 27 & 24 \end{bmatrix} + \begin{bmatrix} 10 & 35 & 5 & 20 \\ 4 & 14 & 2 & 8 \\ 12 & 42 & 6 & 24 \end{bmatrix}")

text4 = MathTex(r"\begin{bmatrix} 3 & 9 & 5 \\ 9 & 4 & 2 \\ 7 & 3 & 6 \end{bmatrix} \begin{bmatrix} 5 & 7 & 2 & 4 \\ 3 & 6 & 9 & 8 \\ 2 & 7 & 1 & 4 \end{bmatrix}", r"&=", r"\begin{bmatrix} 52 & 110 & 92 & 104 \\ 61 & 101 & 56 & 76 \\ 56 & 109 & 47 & 76 \end{bmatrix}")

tt1 = Tex("(Columns of A) times (Rows of B)").shift(UP).shift(UP)
tt2 = Tex("Compute the outer products").shift(UP).shift(UP)
tt3 = Tex("Sum the outer products").shift(UP).shift(UP)

class Multiply(Scene):
    def construct(self):
        self.play(Write(text1))
        self.wait(0.5)
        self.play(Write(tt1))
        self.play(ReplacementTransform(text1, text2))
        self.wait(1.0)
        self.play(ReplacementTransform(tt1, tt2))
        self.wait(0.5)
        self.play(ReplacementTransform(text2, text3))
        self.wait(1.0)
        self.play(ReplacementTransform(tt2, tt3))
        self.play(ReplacementTransform(text3, text4))