# Is there a common set of modules for user-defining-quantum-gate for QISKit

I am wondering if there exists a common library or a set of modules for user-defining-quantum-gate for QISKit.

If it does, could you tell me?

By referring to Define Quantum Gates and How to define user's quantum gates?, I have created 6 modules for IBM Q simulator such as CZ gate and CCZ gate (uploaded here) since they were not built in QISKit standard gates.

However, since the gates such as CZ gate and CCZ gate seems pretty common to use, I am wondering if anybody already opens their gates to the public.

## 1 Answer

For the moment, there is no publicly available repository of custom gates to my knowledge.

If you want I have defined some for my own use. You can find the implementation here but:

• The "gates" implemented are more algorithms than gates.
• If you plan to re-use some of the gates, take a look at the license.

Be also aware of the fact that the gate hierarchy will probably change in a near future (see #316, #476, #591). Even if the changes should be backward compatible, we don't know how the CompositeGate class will be changed at the moment.

• Thank you very much for the information! I will keep in mind the possible change of CompositeGate. Meanwhile, I will create some gates such as CZ, CCZ, CCCX by myself and open them to the public. – Bick Jul 13 '18 at 14:49