Main Question or Discussion Point
As a double major in physics an electrical engineering, I noticed that graphical convolution is used in both signal processing and quantum mechanics. In my signals course I couldn't help but notice that sometimes the professor would just convolved the function from straight integration, and other times we will have to break the integral into different intervals using Graphical convolution method. The graphical method seems more like a general way of solve convolution problems. Is graphical convolution used when the functions you are to be convolved aren't causal, or that the functions aren't equal to zero when t<0?