using double shift strategy to obtain eigenvalue from large general matrix
'Francis_QR_theory.ipynb' is thoery part and 'doubleshift_QR.ipynb' is code part.
references: https://people.inf.ethz.ch/arbenz/ewp/Lnotes/chapter4.pdf
using double shift strategy to obtain eigenvalue from large general matrix
'Francis_QR_theory.ipynb' is thoery part and 'doubleshift_QR.ipynb' is code part.
references: https://people.inf.ethz.ch/arbenz/ewp/Lnotes/chapter4.pdf