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Polynomial regression and model comparison

Welcome back, in my previous post I described how we can perform linear regression using normal equation in Dynamo and I left with a question "what if the input and output are not linearly dependent?” Let’s say we have a hypothesis that the housing price doesn’t depend on floor area and number of rooms linearly but it has a following relationship as y = a_{0} * x_{0} + a_{1} * x_{1} + a_{2} * x_{2} + a_{3} * x_{1} * x_{2} + a_{4} * x_{1}^2 + a_{5} * x_{2}^2 \: where x_{0} = 1, \: x_{1} is floor area and x_{2} is number of rooms. Then we can introduce few new parameters x_{3} = x_{1} * x_{2}, \: x_{4} = x_{1}^2, \: x_{5} = x_{2}^2 and then perform the linear regression to find the coefficient matrix. The Dynamo graph to setup the feature vector looks as follows. Once the feature vector is setup rest all is same as previous linear regression example. Note that the price prediction for a given floor area and rooms we need to again construct the same feature vector. ...