Which block in simulink library should I choose for the H_infinity controller.

I've got this pic that I found in my search implementation of an H-infinity controller and a boost converter:

My question, is how to choose the H_infinity block from the library of simulink? and what is the block connected to it in its right hand side, how is it called?

Thanks!

[Aquatris]

It probably is a custom subsystem which probably has a state space block inside. So you cannot find it in the library of simulink unless it is added as a custom library block.

You can see the down arrow symbol at the left bottom side of the block, which indicates it is a subsystem.

As for the signal connecting from the right side to the block, as with any other feedback controllers, it is connected to the error signal, which in this case a step block (reference signal) minus the output of your system.