_S_p_l_i_n_e _I_n_t_e_r_p_o_l_a_t_i_o_n
	
	     spline(x, y, n=3*length(x), xmin=min(x), xmax=max(x),
	             method="fmm")
	
	_A_r_g_u_m_e_n_t_s:
	
	         x,y : vectors giving the coordinates of the points
	               to be interpolated.  Alternatively a single
	               plotting structure can be specified.
	
	           n : interpolation takes place at n equally spaced
	               points spanning the interval [xmin, xmax].
	
	        xmin : left-hand endpoint of the interpolation
	               interval.
	
	        xmax : right-hand endpoint of the interpolation
	               interval.
	
	      method : this specifies the type of spline to be used.
	               Possible values are "fmm", "natural" and
	               "periodic".
	
	_D_e_s_c_r_i_p_t_i_o_n:
	
	     spline performs cubic spline interpolation of the given
	     data points.  It returns a list containing components
	     x, and y which give the ordinates where interpolation
	     took place and the interpolated values.
	
	     If method="fmm", the spline used is that of Forsythe,
	     Malcolm and Moler (an exact cubic is fitted through the
	     four points at each end of the data, and this is used
	     to determine the end conditions).  Natural splines are
	     used when method="natural" and periodic splines when
	     method="periodic".
	
	_R_e_f_e_r_e_n_c_e_s:
	
	     Forsythe, G. E., M. A. Malcolm and C. B. Moler (1977).
	     Computer Methods for Mathematical Computations.
	
	_S_e_e _A_l_s_o:
	
	     approx, approxfun, splinefun.
	
	_E_x_a_m_p_l_e_s:
	
	     x <- 1:10
	     y <- rnorm(10)
	     plot(x, y)
	     lines(spline(x, y))