Function finance::npv

pub fn npv(rate: f64, vals: &[f64]) -> f64

In finance, the net present value (NPV) or net present worth (NPW)[1] is a measurement of the profitability of an undertaking that is calculated by subtracting the present values (PV) of cash outflows (including initial cost) from the present values of cash inflows over a period of time. Incoming and outgoing cash flows can also be described as benefit and cost cash flows, respectively. see definition: https://en.wikipedia.org/wiki/Net_present_value