Structured singular values and pseudospectra play an important role in assessing the properties of a linear system under structured perturbations. Structured Eigtool is a free Matlab interface for plotting structured pseudospectra. In particular, it supports the computation of real, skew-symmetric, Hermitian and Hamiltonian pseudospectra. Structured EigTool is heavily based on the EigTool  software package for plotting unstructured pseudospectra and inherits much of its interface.
Structured pseudospectra examples
Real pseudospectrum of the Demmel matrix
Skew-symmetric pseudospectrum of the Rump matrix
Download Structured Eigtoolseigtool.tar.gz, seigtool.zip (beta version, August 2009)
This code is research code. If you find bugs, please let us know. If you publish a research paper using this code, we will appreciate if you cite the paper  describing our implementation.
- T. G. Wright, Eigtool, http://www.comlab.ox.ac.uk/pseudospectra/eigtool, 2002.
- M. Karow, mu-values and spectral value sets for linear perturbation classes defined by a scalar product, submitted, 2007.
- M. Karow, E. Kokiopoulou and D. Kressner, On the computation of structured singular values and pseudospectra, submitted, August, 2009.