I created an harmonic with the following command:
 where time is a trend series. I expected a zero vector,
 but the program returns something which is very close to
 zero but not exactly, as shown in the tabulation

    Obs            b2

  1981:1  1.22461e-016
  1981:2 -2.44921e-016
  1981:3  3.67382e-016
 and in the graph, which is not a straight line at y=0.

 I understand this is due to the numerical accuracy at which the program works,
 but I wonder if it's possible to set an option to show 0 whenever
 values are lower than a fixed level (say 10^-5).

 Marco Marini