[Gretl-users] Re: Retrieve day of easterday() as proper integer

On Fri, 8 May 2020, Artur Tarassow wrote: > I've stumbled over this weird thing trying to retrieve the day of > Easter Sunday applying the easterday() function as shown in the help > text. > > However, it seems that scalar "d" is not a proper integer as trying > to restrict the sample to a single day fails with the error message > "No observations would be left!". Replacing "d" in the "smpl" command > by 5 works though. This is using latest git on Ubuntu 19.10. > > <hansl> > clear > set verbose off > nulldata 200 > setobs 7 2015-01-01 --time-series > > series year, month, day > isoconv($obsdate, &year, &month, &day) > > scalar e = easterday(2015) > scalar m = floor(e) > scalar d = 100*(e-m) [...] Adding at this point   printf "4.05 = %.15f\n", 4.05   printf "d = %.15f\n", d   eval d == 5 reveals   4.05 = 4.050000000000001   d = 4.999999999999983   0 So round() will take d to 5, but not floor(). Hansl doesn't do integer arithmetic -- and couldn't in this case anyway since e = 4.05, coding for the 5th of April. It seems to me easterday() would be better returning a 2-vector holding month and day. As things stand you have to use round() on the day, or take this approach: edate = sprintf("%.2f", easterday(2015)) scalar m, d sscanf(edate, "%d.%d", m, d) eval d == 5 # gives 1