January 7th, 2004, 6:38 pm
People certainly use optimizers and regression-like techniques to fit volatility surfaces, both implied and local. There are various methods of vol surface parameterization, many of which tend to be more stable and practical in the long term compared to the Dupire formula.The only greek I have seen as a regressand (or whatevery you call the dependent coefficient) is the Delta. That is, implied vol is most simply practically fit as either a function of time and delta or time and strike.