Let’s say I have 2 arrays (set of coordinates):
x[]={x0,...,xN}
y[]={y0,....,yN}
If I want to know some y(x) I can just calculate the linear interpolation between some points of the array. x is the position of moving particle, so it increases with time. I can keep track of the lower and upper values of x[] for the linear interpolation, and find y(x) easily. However, it’s just tedious to have those lines of code in my script checking lower and upper values all the time.
I thought of doing this defining a TGraph object with x[] and y[], so I can just use TGraph::Eval(x). I’d like to know how this function finds the lower and upper values for x and if this significantly slower for large N