Change Y-Variable to Ln Y in Gnuplot: How-To Guide for Linear Graphing

[VenaCava]

Is there an easy way to change your y-variable in Gnuplot to ln y without changing the source data file?
I already tried "set log y" but that only changed the y-axis scale, not the actual y-values.
Right now I'm plotting an exponential decay and I wanted to make it a linear graph (lny vs time).

Thanks

 

[alphysicist]

Hi VenaCava,

Is there an easy way to change your y-variable in Gnuplot to ln y without changing the source data file?
I already tried "set log y" but that only changed the y-axis scale, not the actual y-values.
Right now I'm plotting an exponential decay and I wanted to make it a linear graph (lny vs time).

Thanks

I'm not sure if this is what you want, but if you are using a data file "data.txt" with x and y columns, you can plot the natural log of the y columns with the command:

plot 'data.txt' u 1:(log($2))