U. Helmke et al., DYNAMICAL-SYSTEMS THAT COMPUTE BALANCED REALIZATIONS AND THE SINGULAR-VALUE DECOMPOSITION, SIAM journal on matrix analysis and applications, 15(3), 1994, pp. 733-754
The tasks of finding balanced realizations in systems theory and the s
ingular value decomposition (SVD) of matrix theory are accomplished by
finding the limiting solutions of differential equations. Several alt
ernative sets of equations and their convergence properties are invest
igated. The dynamical systems for these tasks generate flows on the sp
ace of realizations that leave the transfer functions invariant. They
are termed isodynamical flows. Isodynamical flows are generalizations
of isospectral flows on matrices. These flows evolve on the actual sys
tem matrices and thus remove the need for considering coordinate trans
formation matrices. The methods are motivated by the power of parallel
processing and the ability of a differential equations approach to ta
ckle time-varying or adaptive tasks.