Software to Compute Pseudospectral Abscissa

Below you can access the Matlab routines to compute the pseudospectral abscissa of a large-scale matrix-valued function. The main routine to call is psa_subs_init. See the sample calls file before using the routines. To learn the details of the input and output arguments, type help psa_subs_init in the Matlab command window.

  1. Bullet Download the routines (Last update: October 10, 2016)

  2. Bullet Sample calls

These routines can specifically be used to compute the pseudospectral abscissa of

  1. Bullet a large matrix,

  2. Bullet a matrix polynomial,

  3. Bullet a delay eigenvalue problem,

and are implementations of the approach described in the following paper.

  1. Bullet K. Meerbergen, E. Mengi, W. Michiels and R. Van Beeumen. Computation of Pseudospectral Abscissa for Large Scale Nonlinear Eigenvalue Problems. Submitted to IMA J. Numerical Analysis.

The figure on the left above concerns a delay example, the exact data is available here. The figure on the right concerns the butterfly example, which is a quartic matrix polynomial available in the collection NLEVP.