invr - inversion of (rational) matrix
If H is a polynomial or rational function matrix, invr computes H^(-1) using Leverrier's algorithm (see function code)
s=poly(0,'s') H=[s,s*s+2;1-s,1+s]; invr(H) [Num,den]=coffg(H);Num/den H=[1/s,(s+1);1/(s+2),(s+3)/s];invr(H)