Hi, This is a practical question and I am sure there are many statisticians can give me a hand. I have 500 time series data (500 rows), each row contains 100 intervals, i.e., on each row, I have X1, X2, ..... X100. I am trying to reduce the dimension of this input because the data at the end of each row does not have significant meaning to the project I am doing. I used cubic splines on ea. row -- ns(row, df = 10) , and decided to reduce the dimension to 10. Then I generated the new feature by X_new = W*X, where W is obtained from ns(row, df = 10). Now everything seemed perfect and I was able to fit the logistic regression on the new inputs (500 rows, ea. row has only 10 X's). After I computed the coefficients for this reduced model, I want to map these coefficients back to the original problem. i.e., the new coefficients has 10 betas, but I actually want 100 betas that I can use to predict the response from the raw inputs. I donot know how to do this. Any comments are highly appreciated. thanks. [[alternative HTML version deleted]]