Curve fit tool and log scale

Hello!

I have a series of data and using the custom equation, I could fit the data on the theoritical equation. I would like to see the graph and fit curve in log scale but I don't know I to change the x values in log scale. Coyuld you please let me know how to do it? Haev a nice day!

Hye Rim

Answer 1

[Arnaud Miege]

From the curve fitting tool, once you're done with the fitting, click on File -> Generate Code to generate the MATLAB code for your fit. You can then run that code with whatever data you want, but more to the point you can also modify it. Find the part of the code where the plotting is done, and replace the plot command by semilogx, as Laura suggested.

[Hye Rim]

Arnaud,

Thanks very much for your help. It was very helpful for the trouble shooting ! :)

[Yoav Romach]

Bumping this very old thread.

This no longer works (not sure if it's the new curve fitting toolbar or something else). When I replace plot with semilogx i get this:

Error using semilogx
Conversion to double from cfit is not possible.

Error in temp (line 70)
h = semilogx( fitresult{1}, xData, yData );

Anyone got a fix?

[Ali]

same here as above comment.

[Manan Thakkar]

after the plot command

 set(gca,'XScale','log')

should do the job. I am using Matlab R2014b and the above works nicely.

[armin farshbaf]

this way you could only get at base 10 logarithm, do u have any idea for base 2 ?!

[Igor Gitelman]

just take

 log2(x) 

from yor data - x.

Answer 2

[Laura Proctor]

I think you're looking for the function SEMILOGX.