Thread Subject: a question about lmi

I have two Lmis to solve,and I use lmi toolbox.

The question is:
the first lmi I use a matrix variable X(s.t lmi(1,[4,1])).
but in the second lmi,I have to use the inverse of the variable X.
How can I represent the inverse of variable X in the second without define a new variable?

Thanks for help

Hi Xiao

This is not an LMI if it depends on both X and inv(X). The L stands for
"linear" (with respect to X). May be there is a way to rewrite it as a
linear expression in X

HTH
- pascal

"Xiao Ma" <xma4@utk.edu> wrote in message
news:gl62tu$mik$1@fred.mathworks.com...
>I have two Lmis to solve,and I use lmi toolbox.
>
> The question is:
> the first lmi I use a matrix variable X(s.t lmi(1,[4,1])).
> but in the second lmi,I have to use the inverse of the variable X.
> How can I represent the inverse of variable X in the second without define
> a new variable?
>
> Thanks for help