Notionals
Key Notionals in Interest Fn refers to a read-only 1D-array array containing the notionals N₁, N₂ , ... , Nₙ corresponding to the amortization dates D₁, D₂ , ... , Dₙ, as described at Amortization
The data here are of interest only in the case of amortization, i.e. only if an object of type Amortization is supplied in Amortization