How can i replace this code to fast up?

2 次查看（过去 30 天）

subha 2014-8-5

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/146305-how-can-i-replace-this-code-to-fast-up

编辑： subha 2014-9-25

 for i=1:500,
    subplot(23,23,i);
    x=vishid(:,i);
    imagesc(reshape(x,imagesize));
    colormap gray;
end

Here,vishid is 784*500 matrix, imagesize=28*28

2 个评论
显示无隐藏无

Geoff Hayes 2014-8-5

在 MATLAB Online 中打开

Subha - the above code is trying to create 500 subplots within the figure, so it may take some time! :) Adding a drawnow command after the colormap gray line shows how the first 30-40 subplots get drawn relatively quickly, but over time, it takes longer and longer to add the newest subplot to the figure. Even just doing the above with something as simple as

 for k=1:500
    h = subplot(23,23,k);
    set(gca,'XLim',[0 1]);
    drawnow;
end

takes a long time (this was just to see if the bottleneck had to do with the reshape and imagesc - not the case).

Is there a need to show all 500 subplots on the same figure, or could you break it into two figures of 250?

subha 2014-8-5

Thanks for your post. Its not necessary to show all 500 plots in a same figure, But it will be better, if it is in same.

If time reduce by implementing this in more than one figure, i am happy about it

请先登录，再进行评论。

请先登录，再回答此问题。

回答（3 个）

Jan 2014-8-5

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/146305-how-can-i-replace-this-code-to-fast-up#answer_147526

Do you really need 500 images with separate axes objects? You can draw 500 im ages in one axes, when wet the coordinates appropriately. This would be much faster.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Image Analyst 2014-8-6

I totally agree. 500 subplots is absurd. Most of the space will be taken up be white space and you won't see the images.

Matt J 2014-8-6

Whether it's worthwhile depends on how well you need to see the images. Thumbnail views have their uses.

请先登录，再进行评论。

Matt J 2014-8-5

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/146305-how-can-i-replace-this-code-to-fast-up#answer_147524

在 MATLAB Online 中打开

Making the figure invisible until all subplots have been established might help,

   h=figure; 
   set(h,'Visible','off')
    for i=1:500,
        subplot(23,23,i);
        x=vishid(:,i);
        imagesc(reshape(x,imagesize));
        colormap gray;
    end
   set(h,'Visible','on')

2 个评论
显示无隐藏无

subha 2014-8-5

Thanks.Actually, in my case, already my figure appears only after it plots all the 500 plots. so, i am not sure, this will help. Let me try again and come back to u

subha 2014-8-5