**Parameter dependent quasiseparable systems **

Fast solution of shifted linear systems, with applications to
matrix equations with quasiseparable coefficients and to the
computation of functions of quasiseparable matrices.
This is companion software to the manuscript *Efficient Solution of Parameter Dependent Quasiseparable Systems*(with Y. Eidelman and L. Gemignani).

**Structured QR/QZ **

Code for fast computation of eigenvalues of
companion matrices using a structured version of the implicit
QR method.
**Without compression: **

This is a Fortran 90 implementation of the algorithms described
in the paper *A Fast Implicit QR Eigenvalue Algorithm for Companion Matrices*(with D. A. Bini, Y. Eidelman, L. Gemignani and I. Gohberg, LAA 2010).

**With compression: **

Companion software to the article
*Implicit QR with Compression*(with Y. Eidelman, L. Gemignani and I. Gohberg, Indag. Math. 2012).

**Structured QZ for companion pencils **

Code for fast computation of generalized eigenvalues of companion pencils. The single-shift version
is companion software to the article *Implicit QR for companion-like pencils*(with Y. Eidelman and L. Gemignani, Math. Comp. 2016). The double-shift version implements the algorithm described in the preprint

*A real QZ algorithm for structured companion pencils*(with Y. Eidelman and L. Gemignani, 2016).

**Approximate polynomial GCD**

Matlab code for fast computation of approximate polynomial GCD.
This is an implementation of the fast algorithm described in the paper *A fast algorithm for approximate polynomial gcd based on structured matrix computations*(with D.A. Bini, Operator Theory 2010).

**Multiplication Matrix GCD**

Matlab code for fast implementation of approximate polynomial GCD
with one exact polynomial. Companion software to the paper
*Extended companion matrix for approximate GCD*(with O. Ruatta), presented at SNC 2011.

**Condition geodesics in matrix spaces**

Companion software to the paper *The condition metric in the space of rectangular full rank matrices*(with J.-P. Dedieu, SIMAX 2010).