Symbolics - Identity matrices for beginners

I’m trying to relearn linear algebra for the basics of deep-learning. I also want to bootstrap myself into using Symbolics.jl at the same time. I used to enjoy owning MuMath back in the day.

I have basic 2 x 2 matrices hand-loaded with Symbolics variables, and they are multiplying, and displaying nicely.

I would like to know how to construct identity matrices in a conventional manner. I made a 2x2 Identity using Matrix{Float64}(I,2,2) This gives the appearance of working, but I don’t feel right about constraining the identity matrix to Float64.

How should I properly make a symbolic identity matrix?

Why not just use I?


Thanks Chris, I was hoping that would be the answer :slight_smile:
Ouch looking at my code - I was using I - didn’t use my subscript. The answer is I failed to find it by searching the documentation. It does appear in Pluto Live docs - once I knew what it was.
What can I read to get a foundation in CA in the style of Symbolics?

I’d like to not be more than 10% baffled by

scalar I is equal to true. * must be doing the scalarized operation? That might be worth an issue.

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Issue #367