# How to construct a multi-qubit controlled rotation with variable angle? [duplicate]

I'm trying to construct a circuit that performs the quantum transformation :

Where $$f$$ is some function. Is there a way to do it without going through every possible value of $$i$$ ?

• This has essentially been asked before. You probably want to take a look at my answer here: quantumcomputing.stackexchange.com/a/10282/1837 May 28 '20 at 14:28
• @DaftWullie Okay, I figured it out, thanks May 28 '20 at 14:53