*!version 1.0.0  6-10-98  Joseph Hilbe  STB-45 dm60
* trigamma function: immediate command
* Ex: trigami (numnber) ; the trigamma value, if valid, will follow

program define trigami
  version 5.0
  #delimit ;
  local tg = ( -lngamma(`1'+.002) + 16*lngamma(`1'+.001)
               -30*lngamma(`1')   + 16*lngamma(`1'-.001)
               -lngamma(`1'-.002) ) / .000012;
  #delimit cr
  noi di %8.4f `tg'
end