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Matrix Multiplication

matrixmultiplication.xyz

11–20 of 135 posts

Re: Matrix Multiplication

#11
I like the idea, but my brain is wired differently.

Usually, when I do matrix multiplications, the rows on the left side transition to the columns on the right side. In the example, the 1 goes to 2, 2 to 6, 1 to 1.

The animation completely confused me, because it looks like being reversed, but the result is the same.

Maybe, make this a visualization option?

Re: Matrix Multiplication

#14

I like the idea, but my brain is wired differently. Usually, when I do matrix multiplications, the rows on the left side transition to the columns on the right side. In the example, the 1 goes to 2, 2 to 6, 1 to 1. The animation completely confused me, because it looks like being reversed, but the result is the same. Maybe, make this a visualization option?

Essentially, that is how I was taught and do matrix multiplication as well. But this sliding window approach is also interesting. Although, it would be a bit complex to understand how to fill in the results based on the sliding window.

Re: Matrix Multiplication

#15

This is nearly how I think of it, but for me I do one column of the second matrix at a time. I think it is clearer that way. This way makes it look like there is some kind of staircase thing going on which there isn't really.

That was my thought too - I was taught to do one row of the first matrix with one column of the second matrix at a time.

I found the whole staircase thing quite confusing.

Re: Matrix Multiplication

#19
This is a cool example of what Bret Victor calls an "Explorable Explanation" [0]. That said, I feel that it's more important to understand how and why matrix multiplication corresponds to a composition of linear transformations than learning the actual mechanics of doing the computation. You can get good at matrix multiplication without knowing what is going on. I view that as a less valuable activity than learning about linear transformations (vector-space structure preserving mappings) between finite dimensional vector spaces.

[0] http://worrydream.com/ExplorableExplanations/

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