No such thing exists. It's part of certain stochastic volatility process that I've derived a new means of solution for because the paper that it was published in used the Adam's bashforth discretization method in the time domain which is computationally prohibitive since you have to evaluate it for every strike price and every variation of the perimeters so it would be very costly during optimization so therefore the solution is to Fourier transform into the frequency domain and then perform in orthogonal polynomial expansion and then you end up with a method where you can approximate the solution with like 99.9% accuracy using only for instance the first 20 or 30 need the infinite degree accuracy so it's far more computationally efficient because these basis functions can be precomputed ahead of time, memoized basically or cached. The error of the solution is no greater than the magnitude of the last term omitted from the expansion therefore if you know the duration for which you want to calculate this expectation then you can calculate exactly how many terms you need to reach the desired level of accuracy to reach the one penny level of resolution or subpenny if such a thing is being used
The solution method is not entirely new but no one has written about using the orthogonal polynomial expansion for the fractional Ricatti process in finance.
I'm trying to decide whether I should just sit and using myself or license it to some trading houses or something
The technique is described here
https://www.sciencedirect.com/science/article/pii/S0307904X15003893