I am going to reduce the order of my state-space model, that is I am using "hsvd(sys)" in Matlab to get an approximation of what should be the order of my ROM. I have been able to reduce the order of my model from 240 states to 30 states, i.e. only 30 states appear to have a high value in the hsvd plot. I have the new sensitivity matrices based of rsys=balred(sys,30), though I need to know what are the states that have been deleted/ what are the states that my new ROM (rsys) keeps involved in the model.

I sincerely appreciate any suggestions and thoughts on this matter to help me deal with this issue.