“…Both in BS and Heston model, one can derive the pricing partial differential equation (PDE) in several different ways, for example (Wilmott, 1998;Rouah, 2013;Hull, 2018) using arbitrage arguments with self-financing trading strategies, approaches with martingale measures or the Fokker-Planck equation for the transition probability density function. Although semi-closed formulas have been widely used in practice for a long time, only recently Daněk and Pospíšil (2020) showed that for certain values of model parameters these formulas can bring serious numerical difficulties especially in evaluation of the integrands in these formulas and their implementation therefore sometimes requires a demanding high precision arithmetic to be adopted.…”