I am looking for the B-field of a real coil. So a straight piece of pipe with some current density. Is it correct that there is no analytical solution to this? It would be enough if I had the field of a current rotating in a cylinder obviously. I am working on some Biot-Savart but either I get some ugly double roots or roots mixed with trig functions in my integrals. Does anyone know more? I do need the off center field as well!