[Quantlib-users] Queries on the impact of barrier hit on Barrier pricing

[Ashish B. <ash...@gm...>]

Dear team,

I need some guidance on the pricing of the barrier option using
the FdBlackScholesBarrierEngine in the event that the barrier is hit:
1. for Down-Out, when I pass the spot less than the barrier, I get
RunTimeerror for interpolation range. Should I block the pricing at all in
this case? Can't the engine handle it?
2. For Down-in, I am getting the same error whereas the option gets
activated and is still live then why is this not priced by the engine? Am
I doing something wrong?

What is the difference between FdBlackScholesBarrierEngine
and AnalyticBarrierEngine? I compared a few results and found a slight
difference in values. Any suggestion on which one to use?

Any help would be appreciated.

Thanks
Ashish