[Question] How to Calculate Eigenvectors and Eigenvalues

[GaudiestTooth17]

Has anyone done this before or have any tips about how to proceed? The documentation says that this feature still needs to be documented and I'm new to nim and neo.

[andreaferretti]

For eigenvalues, there is a dedicated function https://play.nim-lang.org/#ix=2LSo

import neo

let m = matrix(@[
    @[1f64, 2, 3],
    @[4f64, 5, 6],
    @[7f64, 8, 9]])
let e = m.eigenvalues()
echo e.real
echo e.img

For normal matrices, the eigenvectors can be read from the column vectors of its Schur decomposition (m.schur()), but I do not recall whether there is something more general than that in Neo

[andreaferretti]

Something like this should work:

import neo

let
  m = matrix(@[
    @[1f64, 4, 7],
    @[4f64, 5, 8],
    @[7f64, 8, 9]
  ])
  s = m.schur()
  e = s.eigenvalues.real
  f = s.factorization
for i in 0 .. 2:
  echo e[i]
  echo f.column(i)

https://play.nim-lang.org/#ix=2LSx

[GaudiestTooth17]

Thank you!