(gretl from yesterdays cvs on kubuntu linux).
I found that if I create periodic dummies before calling a function that
also creates these dummies, the dummies appear twice. So the external dummies are
passing inside the function in some way. I think this should not occur.
function seasonal_function(series Y)
set echo on
list seasonal = dq*
list seasonal print
ols Y time seasonal
return series dseas
series dreskwh = seasonal_function(reskwh)