There isn’t one and there should be. I have been looking into starting development once my real life work gets a bit less hectic.
Currently available fitting apps for the desktop Pc include EFT, closed source; Python Fitting Assistant, open source but written in Python; and a few others built into bigger apps like EveHQ.
Basically, I have option of programming a app from scratch (fun but long), or trying to port Pyfa.
Porting Pyfa may be possible, although Apple have an annoying policy discouraging the use of interpreters in the appstore… although this doesn’t stop me from using py2objc and targeting jailbreak devices through the cydia app store equivalent.
I think I will start to prototype an app store variant, written from the ground up in objc, should be a fun project, although it might be hard to find the spare time require ;-).