gsaccum	- Accumulate point into data set
	gsacpts - Accumulate points into a data set
	  gsadd - Add two surfaces
	gscoeff - Get coefficients 
	 gscopy - Copy one surface to another
	  gsder - Evaluate the derivatives of a surface
       gserrors	- Calculate chi-square and errors in coefficients
	 gseval	- Evaluate surface at x and y
	  gsfit	- Fit surface
	 gsfree - Free space allocated by gsinit
	 gsinit - Make ready to fit a surface; set up parameters of fit
	gsrefit	- Refit surface, same x, y and weight, different z
       gsreject	- Reject point from data set
      gsrestore - Restore surface parameters and coefficients
	 gssave - Save surface parameters and coefficients
	gssolve	- Solve matrix for coefficients
	gsstati - Get integer parameter
	gsstatr - Get real parameter
	  gssub - Subtract one surface from another
       gsvector - Evaluate surface at an array of x and y
	 gszero - Zero arrays for new fit