>> axis([0,17,0,10,0,100])<BR>>> subplot(1,2,2),<BR>>> contour(v2);<BR>>> hold on;<BR>>> x=1:1:17;y=1:1;10;<BR>>> [xx,yy]=meshgrid(x,y);<BR>>> [Gx,Gy]=gradient(v2,0.5,0.6);<BR>>> quiver(xx,yy,Gx,Gy,'r'),<BR>??? Error using ==> quiver<BR>The length of Y must match the number of rows of Z.<BR>这个问题呢??什么意思??