Calculation of Pseudospectra by the Arnoldi Iteration

Kim-Chuan Toh, Lloyd N. Trefethen
1996 SIAM Journal on Scientific Computing  
The Amoldi iteration, usually viewed as a method for calculating eigenvalues, can also be used to estimate pseudospectra. This possibility may be of practical importance, because in applications involving highly nonnormal matrices or operators, such as hydrodynamic stability, pseudospectra may be physically more significant than spectra.
doi:10.1137/0917002 fatcat:7j7lyj23gjhjbp2ztjbmpf7eqm