What algorithm(s) does LinearAlgebra.eigvals employ for a general, i.e., non-symmetric, non-triangular matrix?
The Schur decomposition of a general matrix (the specific algorithm being known as QR iteration), as provided by LAPACK.
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It calls LAPACK.geevx! under the hood, i.e. LAPACK: dgeevx (assuming Float64 precision).
BTW, I recommend @descend eigvals(A) from Cthulhu.jl to descend down the call tree and investigate things like this. This will lead you to these lines.
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