Re: On optimal scaling of a matrix

Dear Edgar C. Tamayo,

For Matlab files please the home page of the book
  www.chembio.ntnu.no/users/skoge/book.html
under matlab and then under Chapter 3 (condmin.m).

The file is given below. It uses the mu-synthesis toolbox, but
you could easily rewrite it to use the Robust Control toolbox.
There are also files for only input or only output scaling.

----
function gmin = condmin(Gf)
% Minimize cond.no. with both input and output scaling
% WARNING: May be inaccurate because of inaccurate mu-calculation
%
[dum1,n,m,dum2]=minfo(Gf);
zero = 0*eye(n);
H = abv( sbs(zero, minv(Gf)), sbs(Gf, zero));
blk0=[1 1]; blk1=blk0;
for k=2:n
  blk1 = [blk1; blk0];
end
blk2=blk1; blk=[blk1; blk2];
mu1=mu(H,blk,'Uc'); gmin1=sel(mu1,':',1);
gmin=mmult(gmin1,gmin1);
----
best regards,
Sigurd Skogestad