Choosing between engineering, physics and math is a choice I have been putting off for a long time. I am in my undergrad under engineering physics trying to do it all still by taking 6 courses a semester so that I can still fit in things like real analysis and topology, as well as quantum, EM, and then your typical engineering fare: such as fluid mechanics, heat transfer, etc. As my time until graduate school shrinks I realize I need to start making some decisions. What I'm wondering is, are there are graduate programs in engineering (or other) where you could focus exclusively on mathematical methods? I've also been interested in nuclear engineering in the past, though I have it in my head that it's possible to study functional analysis in a nuclear engineering program, where might I have read that? Is it true?