/// <summary>Determines whether a volatility should be computable that implies a specified option value.
/// </summary>
/// <param name="optionValue">The option value.</param>
/// <param name="option">The option.</param>
/// <returns>
/// <c>true</c> if there should be an implied volatility for the specified option value be available; otherwise, <c>false</c>.
/// </returns>
/// <remarks>The implied volatility of Far-out-of-the-money options can often not be computed. One can design the individual test cases or one may override this
/// method in an individual manner to avoid questionable results in the unit tests.</remarks>
protected override bool IsVolatilityInvertibleOptionValue(double optionValue, IConstantVolatilityStandardEuropeanOption option)
{
/* the option value should be >= 0 and the option price should not be the intrinsic value, see for example the remarks in
* 'Numerical approximation of the implied volatility under arithmetic Brownian motion', J. Choi, K. Kim, M. Kwak (2007),
* applied to a digital option.
*/
return(base.IsVolatilityInvertibleOptionValue(optionValue, option) && (optionValue != option.GetIntrinsicValue()));
}
/// <summary>Determines whether a volatility should be computable that implies a specified option value.
/// </summary>
/// <param name="optionValue">The option value.</param>
/// <param name="option">The option.</param>
/// <returns>
/// <c>true</c> if there should be an implied volatility for the specified option value be available; otherwise, <c>false</c>.
/// </returns>
/// <remarks>The implied volatility of Far-out-of-the-money options can often not be computed. One can design the individual test cases or one may override this
/// method in an individual manner to avoid questionable results in the unit tests.</remarks>
protected virtual bool IsVolatilityInvertibleOptionValue(double optionValue, IConstantVolatilityStandardEuropeanOption option)
{
return(optionValue > MachineConsts.SuperTinyEpsilon);
}
/// <summary>Returns a <see cref="IEuropeanOptionPricer"/> object that encapsulate the current instance.
/// </summary>
/// <param name="constantVolatilityStandardEuropeanOption">A specified European option based on a model with a constant volatility (i.e. Black, Bachelier etc.).</param>
/// <param name="volatility">The volatility parameter.</param>
/// <returns></returns>
public static IEuropeanOptionPricer AsEuropeanOptionPricer(this IConstantVolatilityStandardEuropeanOption constantVolatilityStandardEuropeanOption, double volatility)
{
return(new Wrapper(constantVolatilityStandardEuropeanOption, volatility));
}
/// <summary>Determines whether a volatility should be computable that implies a specified option value.
/// </summary>
/// <param name="optionValue">The option value.</param>
/// <param name="option">The option.</param>
/// <returns>
/// <c>true</c> if there should be an implied volatility for the specified option value be available; otherwise, <c>false</c>.
/// </returns>
/// <remarks>The implied volatility of Far-out-of-the-money options can often not be computed. One can design the individual test cases or one may override this
/// method in an individual manner to avoid questionable results in the unit tests.</remarks>
protected override bool IsVolatilityInvertibleOptionValue(double optionValue, IConstantVolatilityStandardEuropeanOption option)
{
/* the option value should be >= 0 and the (undiscounted) option price should not be Strike-Forward, see remarks in
* 'Numerical approximation of the implied volatility under arithmetic Brownian motion', J. Choi, K. Kim, M. Kwak (2007)
* and apply the call-put parity.
*/
return(base.IsVolatilityInvertibleOptionValue(optionValue, option) && (optionValue / option.DiscountFactor != option.Strike - option.Forward));
}
internal Wrapper(IConstantVolatilityStandardEuropeanOption standardOption, double volatility)
{
m_StandardOption = standardOption;
m_Volatility = volatility;
}