      nlerrors - Compute the fits statistics and errors in the parameters
	 nlfit - Fit the function
	nlfree - Free memory allocated by nlinit
	nlinit - Initialize the fitting routines
	nlpget - Get the values of the fitted parameters
        nlstat - Get the value of an NLFIT parameter
	nleval - Evaluate the curve at a given point
      nlvector - Evaluate the curve at an array of points 
