L_x=10.0;w_0=1.0;lambda=0.6;n=1.0;k_0=2*pi/lambda;N_x=128;Delta_x=L_x/(N_x-1);h=5*Delta_x;N_z=100;plotting=zeros(N_x,N_z);x=linspace(-0.5*L_x,0.5*L_x,N_x);x=x';E=exp(-(x/w_0).^2);z=0;z_plot=zeros(N_z);for r=1:N_zz=z+h;z_plot(r)=z+h;plotting(:,r)=abs(E).^2;E=step(Delta_x,k_0,h,n,E);endfor k=1:N_z/10:N_zplot(plotting(:,k),'LineWidth',1.5)set(gca,'FontSize',14);hold onendpauseclose allfor k=1:N_z/10:N_zy=z_plot(k)*ones(size(x));plot3(x,y,plotting(:,k),'LineWidth',1.5)hold onendgrid onxlabel('x','FontSize',14)ylabel('z','FontSize',14)set(gca,'FontSize',14);pauseclose all出现的错误如下图所示，还请大佬指点迷津！非常感谢！