Synopsis
		sfroots < poly.rsf > root.rsf niter=10 tol=1.0e-6 verb=y sort=

Parameters
		int niter=10 number of iterations   string sort= attribute for sorting   float tol=1.0e-6 tolerance for convergence   bool verb=y [y/n] verbosity flag

Used In
		JSG          seislet/plane seislet/sin2