functions in spydr_psffit.i -

             func getam(hdr,verbose=)  
 
   Determine airmass from the information available in the AC header  
   for use in yfwhm.i procedure.  

             to be called within F(x,a) as  
 
   a = lmfit_lim(a,1)  
   to set limits to the range of possible a values  
   and then to be called as  
   a = lmfit_lim(a,-1)  
   after spydr_lmfit has returned.  
   also, add the extern statement to calling function.  
   also, set the default values for the affected a to 0 (average value between  
   min and max).  

 lmfit_result  
 
struct lmfit_result {  
  /* DOCUMENT lmfit_result -- structure returned by lmfit  
  long	neval;  
  long	niter;  
  long	nfit;  
  long	nfree;  
  long	monte_carlo;  
  double	chi2_first;  
  double	chi2_last;  
  double	conv;  
  double	sigma;  
  double	lambda;  
  pointer	stdev;  
  pointer	stdev_monte_carlo;  
  pointer	correl;  
};  

 s_yfwhmres  
 
struct s_yfwhmres { double xpos, xposerr, ypos, yposerr, pstrehl, pfwhm, xfwhm, xfwhmerr, yfwhm, yfwhmerr, flux, fluxerr, el, elerr, angle, maxim, background;};  

             spydr_lmfit  
 
   Non-linear least-squares fit by Levenberg-Marquardt method.  
   This is a local copy, slightly modified, of lmfit.i (in yutils).  
   For help, please refer to the lmfit document section.  
   In general, use lmfit instead of spydr_lmfit.  

             func yfwhm(image,boxsize=,saturation=,pixsize=,funtype=,  
 
   magswitch=,nwindow=,verbose=,airmass=)  
   image      = 2D image  
   airmass    = airmass. Outputs airmass corrected FWHM values  
   pixsize    = Specify the image pixel size  
   boxsize    = Specify the size of the box of sub-images  
   (usually 4-10 times the fwhm)  
   funtype    = function to use for fit (gaussian,special,moffat  
   saturation = Saturation value (prevents picking saturated stars)  
   magswitch  =  Output flux in magnitude (zp=spydr_zero_point is used)  
   nwindow    = Number of window for UI (default 2)  
   verbose    = Verbose mode (0/1=more chatty)  
   x and y: added 2007jun15 for compatibilty with spydr find mode.  
            if x and y are set, then the interactive mode is turned off,  
            and the (x,y) coordinates are looped on to produce the  
            final yfwhmres (this function loops on the (x,y) and fit  
            each image in turn).