def delta(flag, S, K, t, r, sigma):
"""Return Black-Scholes delta of an option.
:param S: underlying asset price
:type S: float
:param K: strike price
:type K: float
:param sigma: annualized standard deviation, or volatility
:type sigma: float
:param t: time to expiration in years
:type t: float
:param r: risk-free interest rate
:type r: float
:param flag: 'c' or 'p' for call or put.
:type flag: str
"""
b = r
return numerical_delta(flag, S, K, t, r, sigma, b, f)
def delta(flag, F, K, t, r, sigma):
"""Returns the Black delta of an option.
:param flag: 'c' or 'p' for call or put.
:type flag: str
:param F: underlying futures price
:type F: float
:param K: strike price
:type K: float
:param t: time to expiration in years
:type t: float
:param r: annual risk-free interest rate
:type r: float
:param sigma: volatility
:type sigma: float
:returns: float
"""
b = 0
return numerical_delta(flag, F, K, t, r, sigma, b, f)
def delta(flag, S, K, t, r, sigma, q):
"""Returns the Black-Scholes-Merton delta of an option.
:param flag: 'c' or 'p' for call or put.
:type flag: str
:param S: underlying asset price
:type S: float
:param K: strike price
:type K: float
:param t: time to expiration in years
:type t: float
:param r: annual risk-free interest rate
:type r: float
:param sigma: volatility
:type sigma: float
:param q: annualized continuous dividend yield
:type q: float
:returns: float
"""
return numerical_delta(flag, S, K, t, r, sigma, r-q, f)