This post introduces some notes on calculations that use previous values, using filter calculations as an example.
Example:
Filter Formula：Yn = (k * Xn) + (1 – k)*Yn-1 k = 0.2
Filter value Y1 ：Previous filter value at first calculation Yn-1 = 0.0（初期値のまま）
Filter value Y2 ：Previous filter value at first calculation Yn-1 = Xn
As shown in the graph below, different initial behavior results depending on the previous filter value Yn-1 at the initial calculation. Software engineers should be aware that this point may not be mentioned in the software requirements specification.
