Harwell-Boeing matrices

SetDirectory[NotebookDirectory[]]

"/home/student/courses/MATH662/examples/Arnoldi"

A=Import["tols4000.mtx"];

Dimensions[A]

Timing[Λ=Eigenvalues[A];]

m=4000

flop=(10^10)

Δt=N[ (m^3)/flop]

Λ[[3900;;3930]]

Graphics[Point[Map[{Re[#],Im[#]}&,Λ]]]