Statistics - Forward and Backward Stepwise (Selection ...
datacadamia.com › data_mining › stepwise_regressionBetween backward and forward stepwise selection, there's just one fundamental difference, which is whether you're starting with a model: with no predictors ( forward) with all the predictors. ( backward) At each step: we're not looking at every single possible model in the universe that contains k predictors such as in best subset selection but we're just looking at the models that contain the k minus 1 predictors the we already chose in the previous step.
Forward and Backward Euler Methods
web.mit.edu › 10 › WebForward and Backward Euler Methods. Let's denote the time at the nth time-step by t n and the computed solution at the nth time-step by y n, i.e., . The step size h (assumed to be constant for the sake of simplicity) is then given by h = t n - t n-1. Given (t n, y n), the forward Euler method (FE) computes y n+1 as