matlab画对数座标图

close all;
x = [256 512 1024 2048 4096 8192];
y1 = [0.017360, 0.043902, 0.185930, 0.787196, 3.266647, 45.045046]
y2 = [0.000510, 0.000625, 0.000573, 0.000602, 0.000635, 0.000714]
semilogy(x,y1,'b*-',x,y2,'ro-','linewidth',2);
hold on
% semilogy(x,y2,'r.-','linewidth',2);
grid on;
legend('SSDFT','New approcah')


title('Initial Step');           %设置标题行
xlabel('Image Dimension (pixels)');     %设置横座标
ylabel('Time (s)');   %设置纵座标