Synopsis
		sfepisort < in.rsf x=x_file.rsf y=y_file.rsf > out.rsf dist=dist_file.rsf theta=theta_file.rsf epi_x= epi_y= sort=

Parameters
		file dist= auxiliary output file name   float epi_x= referenced epicenter coordinate x.   float epi_y= referenced epicenter coordinate y.   string sort= sort distance[d] (default) or angle[a]   file theta= auxiliary output file name   file x= auxiliary input file name   file y= auxiliary input file name