I am old and after 55 years of professional experience in research (in the area of numerical simulation), I still have a lot of fun with mathematics (almost with the problems I still did not get the solution).
My major concern is not one calculation. In simulation (dynamic process, oil and gas reservoirs,...) most calculations must be repeated zillions of times. So, numerical efficiency is my main concern.
I can be reached by e-mail at email@example.com