When I solved a SDP problem, the number of variables shown in Matlab Command window is 22313 (see the figure), but actually I just declared 509 scalar variables belonging to some matrix variables. I was wondering **why there is such a huge difference**. It seems that inceasing the number of constraints (LMIs in my problem) will increase the number of variables shown in Matlab command window. Hope someone can give me some hints. Thanks a lot.

CVX performs a variety of transformations on the problems you enter into it, in order to convert it into a form that the underlying solvers can handle. These transformations sometimes include the creation of new variables and constraints.

Thank you Michael. Got it!

Hey Michael, sorry for reopening this conversation. I tried to find information about these transformations but I couldn’t find it. Could you point me in the right direction?

Thanks!