fit2fitdr_angle

  FIT2FITDR_ANGLE - Direction ratio (fraction of response in certain direction) from double gaussian fit

   TDR = FIT2FITDR_ANGLE(FITPARAMS, BLANKRESP, THEANGLE)

   Computes the "direction ratio", or the fraction of the total response
   that is in the given angle compared to the opposite angle.

   FITPARAMS is a 5-value vector describing a double gaussian fit to a
   direction tuning curve (FITPARAMS(1) is offset, FITPARAMS(2) is weight
   of first gaussian peak, FITPARAMS(3) is the peak tuning position, 
   FITPARAMS(4) is the variance around the peak, FITPARAMS(%) is the
   weight of the 'null' direction peak):
   Resp = -BLANK + fitparams(1)+...
     fitparams(2)*exp(-angdiff(fitparams(3)-angs).^2/(2*fitparams(4)^2)) +...
     fitparams(5)*exp(-angdiff(fitparams(3)+180-angs).^2/(2*fitparams(4)^2));

   The formula is TDR = Resp(THEANGLE)/ 
                         (Resp(THEANGLE)+Resp(THEANGLE+180))

   See also: OTFIT_CARANDINI, FIT2FITOI, FIT2FITDIBR