plot 2 curves with 'very close' y values

Hello,

I would like to know if there is a way in matlab to plot 2 curves on the same plot, that have very close y values (very small differences).

Note: I have tried the 'log' for the y-scale but gave a similar view as the linear!

Thanks

Answer 1

[Azzi Abdelmalek]

plot(t,y1,'or)
hold on
plot(t,y2,'-g')

[Walter Roberson]

plot(t, y1, 'or', t, y2, '-g')

[Sam Alex]

Yes but this plots regular graphs, but what I am saying here that they are so close in terms of their y-scale values

[Image Analyst]

Maybe you want to, or should, plot the difference instead of the value themselves.

[Sam Alex]

It wont work since people should see the exact y-axis since it represents the objective function values, and for some problems, the optimal is unknown so we cant do this

[Azzi Abdelmalek]

What do you want exactly to plot? post your two functions

[Sam Alex]

How can I paste 2 columns, each containing around 10,000 values? Is there a way to attach files here? Thanks

[Azzi Abdelmalek]

Post a link that contains your file

[Image Analyst]

Have you maximized the height of your axes? To as much as full screen or close to it?

See this to upload files: http://www.mathworks.com/matlabcentral/answers/7924-where-can-i-upload-images-and-files-for-use-on-matlab-answers

[Azzi Abdelmalek]

add to your plot

 set(gca,'xscale','log')

[Image Analyst]

Sorry - Windows doesn't support proprietary .rar files.

[Sam Alex]

This: set(gca,'xscale','log') did not change a thing to the look of the figure

[Azzi Abdelmalek]

It's not the same plot

[Walter Roberson]

You have not really defined your goal. You know how to plot two lines on the same plot, so you must be talking about something you want to do with the presentation of the lines, but you have not defined what you want the result to be.

[Sam Alex]

It gives a very nice start, but then when they approach the 1.3 they get very similar and again interleaved...any ideas?

[Azzi Abdelmalek]

The variation becomes too small, you have to make several plots in many intervals to see these variations

[Walter Roberson]

Okay, so they get similar and interleaved, and that is a problem because... ? And what would your output look like ideally?

[Sam Alex]

Thanks Azzi. You are an A++ expert!

Answer 2

[José-Luis]

If you want to see the differences and at the same time keep values of your vectors, i would recommend something like this:

 plot(x1d,x2d,'b-'); %your values
 hold on; 
 plot([0 3],[0 3], 'k-'); % 1:1 line

So you have both your vectors in the x and y axes, and the diagonal line shows points of equal value. Below the diagonal one is greater than the other. Vice-versa for above. The further away, the larger the difference.

[Sam Alex]

This does not plot as you say! Where is the line and that you are saying?

[José-Luis]

Edited code: I was not plotting a line but points, please look at my updated answer.

[Sam Alex]

This very nice to compare just two plots right? Is there a generalization to compare more than two plots on the same figure?

[José-Luis]

Not like that, but plotmatrix() could help you for that.

[Sam Alex]

Thank you so much. You are wonderful!

[José-Luis]

Not sure about that, but I'm glad I could help.

Answer 3

[John D'Errico]

So why not just plot the difference?

Or create two plots as a subplot, one with just curve 1, and the second as the difference between the two curves?

Or, have both plots on the same set of axes, with a double y axis?

help plotyy