;+
; NAME:
; jd2fp_doy
;
;
; PURPOSE:
; convert julian days to floating point da of year
;
;
; CATEGORY:
; time conversion
;
;
; INPUTS:
; jd: julian day to convert
;
;
; KEYWORD PARAMETERS:
; YEAR: output variable to contain the year of the jd input
;
;
; OUTPUTS:
; fp_doy - fp_doy of the input julian day
;
;
; EXAMPLE:
; IDL> print, jd2fp_doy(2452033.0, year=year)
;        123.500
; IDL> print, year
;        2001
;
;
;
; MODIFICATION HISTORY:
;
;       Tue Dec 11 11:45:16 2007, Brian Larsen
;		written and tested
;
;-
FUNCTION jd2fp_doy, jd, YEAR=year
compile_opt strictarr


  IF n_elements(jd) EQ 0 THEN $
     message, /ioerror, 'Must specify julian days to convert'

  CALDAT, jd, Month, Day, Year, Hour, Minute, Second 
  
  jd2 = julday(1,1,year)
  jd2 = jd - jd2
  
  fp_doy=jd2+1.5                ; 1 for day 0-1 dfference
                                ; 0.5 for julday 0.5 dumbness

  RETURN, fp_doy
END