February 18th, 2003, 1:04 pm
I've made up a code that solves PDEs for a vanilla call/put. But I cant get i right for exotics, where one needs some more state variables, so therefore I'd appreciate comments (have I missunderstood it all?):1) Suppose I have a european asian with arithmetic discrete average to start with, then I need to keep track of the average (Ai), the value will be V(Si,ti,Ai) in the three dimensional grid.2) If I understands things right, the statevariable (average) will be constant except when we come to a point when a new sample takes place and affects average to date. Since statevariable is constant between sampling points we simply have to solve N regular B & S between these dates. When we start backwards, we know the initial conditions max (AT-K,0). When going backwards we can use the same bounding conditions as usual when S goes to zero or "the limit", but we dont have to set bounding cond for the new statevariable? 3) When we get to a timepoint when sampling occurs, we instead have to use a jump condition when updating the optionvalue (arbitrage condition). 4) And so, if I have completed the grid calc. and whants to pick an optionvalue at the current shareprice and time I can get it from state: V(S0,t0,0) ?