Value function approximation and collocation method

We approximate value function by one of the following:

to calculate the value function until it converges.

On the other hand, we implement one of the smoothing interpolations as mentioned

before such as polynomial OLS, LOESS, LOWESS, kernel regression, smoothing

N-spline, NURBS, and Bezier curve. These interpolations smoothes out the points

o policy functions on the gird.