call/put sign. 1 (default) for call price, -1 for put price,
NULL for Bachelier volatility
forward
forward price. If given, forward overrides spot
df
discount factor. If given, df overrides intr
Value
BS volatility or option price based on cp
References
Choi, J., Liu, C., & Seo, B. K. (2019). Hyperbolic normal
stochastic volatility model. Journal of Futures Markets, 39(2), 186<U+2013>204.
10.1002/fut.21967