Accuracy
Key Accuracy in Impl Vol Spec refers to an optional value ε that is used by the iterative algorithm to determine at each step of the iteration whether a solution has been found.
Specifically, assume the algorithm runs through the iᵗʰ iteration and calculates the price Pᵢ based on the current trial vol Vᵢ.
If the exogenously defined target price is denoted as P, the Vᵢ will be consider a solution and the iteration will stop if ⎢Pᵢ - P⎢ < ε
If omitted, 0.0001 is used.