how to plot with different distance on vertical axis

Hi guys , i have a vector x and a vector y. i want to plot(x,y) but i want : in vertical axis ,the distance from value: 0 to value: 10 is as long as the distance from value: 11 to value: 100 . I don't know how i can do that . Can you help me ? .Thank you very much !

Answer 1

[John BG]

instead of plot(x,y) use function semilogx(x,y)

try it if it really does what you want, would you please be so kind to mark my answer as accepted thanks in advance

John BG

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[Pham Duy Hoan]

Thank you ,but how can i config the distance in vertical axis by my self. When i use semilogy () function, it will automatically excute. For example , i want the distance from value :0 to value :10 is as long as from value : 10 to value : 1000 .

[John BG]

ok, the original question was that you wanted axis x same distance between 0 to 10, than 11 to 100.

If you want the vertical axis then use

semilogy(x,y)

but please note that the picture you have attached to your question is already semilogy(x,y)

If you want y axis to start on 0 and go up to 10 then try the following

semilogy(x,1/10*log10(y))

Regards

John BG

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Answer 2

[Walter Roberson]

In your diagram, you appear to be using linear from 1 up to 10, and then log. There is no built-in facility for that.

What you might be able to do is grab a routine from the File Exchange such as Break Y Axis and once you have used that to split your range, set the upper axes to be log.

I have not investigated to see whether the code there automatically handles Datatips, or whether you need to break up your lines yourself into two parts.

In your text request you are asking for support starting from 0 . This is why I say you are asking for linear: in any log plot, the distance from 1/100 to 1/10 would be the same as the distance from 1/10 to 1 which would be the same as the distance from 1 to 10, and so on. You cannot display all the way down to 0 on a log plot, because log(0) is -infinity.

[John BG]

Dear Walter

my impression is that the question revolves around the values of the axis not the function values.

So to go from [1:step1:1e3] to let's say [0:step2:3] all you need is the logarithm.

Also the question was rewarded from asking about the axis x to asking about the axis y. Some questions are more challenge to get to understand the problem asked rather than the problem itself or what we may guess that the problem is.