Tag Archives: rotation

How do I Create the Identity Matrix in R? Also a bit of group theory.

I googled for this once upon a time and nothing came up. Hopefully this saves someone ten minutes of digging about in the documentation. You make identity matrices with the keyword diag, and the number of dimensions in parentheses. > … Continue reading

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What is an eigenvector?

The eigenvectors of a matrix summarise what it does. Think about a large, not-sparse matrix. A lot of computations are implied in that block of numbers. Some of those computations might overlap each other—2 steps forward, 1 step back, 3 steps … Continue reading

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You know what’s surprising? Rotations are linear transformations. I guess lo conocí but no entendí. Like, I could write you the matrix formula for a rotation by θ degrees: But why is that linear? Lines are straight and circles bend. When you rotate something … Continue reading

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