Function finance_math::am

pub fn am(
    principal: f64, 
    rate: f64, 
    period: f64, 
    year_or_month: bool, 
    pay_at_beginning: bool
) -> f64

In business, amortization refers to spreading payments over multiple periods. The term is used for two separate processes: amortization of loans and assets. It also refers to allocating the cost of an intangible asset over a period of time. see definition: https://en.wikipedia.org/wiki/Amortization_%28business%29