Shell Programming and Scripting

I am trying to fit a plot in gnuplot using logscale. I have 50000 data points. At first I fit plot in this way.

Code:

 f(x) = b + m*x
 fit f(x) "xyMSD-all-mal-cel-iso-bcm-thermo2.dat" using 1:2  via m,b

I got slope value. Then I tried to get slope value at different range as below.

Code:

fit [500:5000] f(x) "xyMSD-all-mal-cel-iso-bcm-thermo2.dat" using 1:2  via m,b

The above code works fine. In next attempt I tried,

Code:

f(x) = b + m*x
fit f(x) "xyMSD-all-mal-cel-iso-bcm-thermo2.dat" using (log($1)):(log($2)) via m,b

Above works fine too. I get the slope value. Then I tried to choose the xrange like below. This is where I have problem. It does not work. Means I dont get the fit between the specified range. For example x range from [500:5000]. When I execute the script I get error message as

Code:

fit [500:5000] f(x) "xyMSD-all-mal-cel-iso-bcm-thermo2.dat" using (log($1)):(log($2)) via m,b

It give error message as

Code:

Read 9999 points 
Skipped 9999 points outside range [x=500:5000] 
No data to fit

Is there any way to achieve this? Appreciate any help

Vijay

It doesn't see any data points in that range. Perhaps you have to tell it to look between log(500) and log(5000) ?

You might also consider using logarithmic scales instead of transforming the data logarithmically.

Code:

set logscale y;