How can i use YALMIP solve LMIs problems that include complex variables?

[xiaobing lu]

Hi, everyone! Can I use YALMIP solve LMIs problems that include complex variables (such as the following LMI) ? What are the main commands? Thanks!!! 

[Johan Löfberg]

Nothing special. Here you would just write [A B+i*w*C;B-i*w*C D] <=0.

YALMIP automatically lifts the complex psd constraint to a real constraints

To define complex decision variables, simply use a flag in sdpvar
http://users.isy.liu.se/johanl/yalmip/pmwiki.php?n=Tutorials.Complex

[Johan Löfberg]

Why are you tagging this question with cplex, when your question involves a semidefinite constraint? (cplex does not support LMIs)

[xiaobing lu]

Thank you very much! The LMI is just a example in my problem(I don't consider its meaning).  And i found another method to solve it in the paper " Vibration control for active seat suspension systems via dynamic output feedback with limited frequency characteristic ". I have another question. I found the results are different when I calculate the robust controller with "robust control toolbox" and 'yalmip toolbox', as follows,

I care about the gamma and K in a controller, and how can treat the different results with the same Rho when I use two kinds of toolbox? Thank you!

[Johan Löfberg]

Looks like a badly conditioned problem (as you get huge numbers in K), so minor differences in the computed solution is not surprising. However, you haven't told us which solver you are using when you use YALMIP