printf("Newton not converged for point (uv)=(%g,%g -> norm_s =%g ) XYZ =%g %g %g \n",u_eval,v_eval,norm_s,nodes_eval(0,0),nodes_eval(0,1),nodes_eval(0,2));
printf("Newton not converged for point (uv)=(%g,%g -> norm_s =%g ) XYZ =%g %g %g \n",u_eval,v_eval,norm_s,nodes_eval(0,0),nodes_eval(0,1),nodes_eval(0,2));
converged=false;
converged=false;
// if Newton diverges, call the routine again with