[Gnuplot-info] Negative logscale axis

[alyflex <al...@gm...>]

Hi, I got some data that I want to plot on a double logarithmic scale, but
since all the y values are negative, I need a negative logarithmic scale,
but I have thus far been unable to make one. Does anyone know how to do
this?

The python script I'm using is the following:

from numpy import *
import Gnuplot, Gnuplot.funcutils
import os, sys, string
import glob
import struct as st
import math
import time

for datafile in glob.glob('*.txt' ):
    g.title('Plot')
    g('set xrange[0.1:100]')
    g('set yrange[-10:-1]')
    g('set terminal gif')
    g('set logscale xy')
    g('set output "'+str(datafile[:-4])+'.gif"')
    g('y(r)=r0+z/r')
    g('r0=0')
    g('z=1')
    g('fit [15:100] y(x) "'+str(datafile)+'" using 1:2 via r0, z')
    g('plot "'str(datafile)+" using 1:2, y(x)')    


And the datafiles look like this:

  0.000000000000000E+000  0.000000000000000E+000
  9.765625000000000E-002  -2.05577406839801     
  0.195312500000000       -1.80843071757366     
  0.292968750000000       -1.59497223855229     
  0.390625000000000       -1.41038643815402     
  0.488281250000000       -1.24415910487246     
  0.585937500000000       -1.09103728309075     
  0.683593750000000      -0.948432020417034     
  0.781250000000000      -0.814990671718170     
  0.878906250000000      -0.690058106734278     
  0.976562500000000      -0.573781621676318     
   1.07421875000000      -0.468133842918065     
   1.17187500000000      -0.380214853165435     
   1.26953125000000      -0.327276191990924     
   1.36718750000000      -0.322127989028048     
   1.46484375000000      -0.347499023048631     
   1.56250000000000      -0.383040585116026     
   1.66015625000000      -0.418903776691791     
   1.75781250000000      -0.451056613640834     
   1.85546875000000      -0.478246521157531     
   1.95312500000000      -0.500379189881943     
   2.05078125000000      -0.517785215206294     
   2.14843750000000      -0.530920312130199     
   2.24609375000000      -0.540249563775338     
   2.34375000000000      -0.546208272940876     
   2.44140625000000      -0.549192158402245     
   2.53906250000000      -0.549557488932987     
   2.63671875000000      -0.547623221032223     
   2.73437500000000      -0.543674138702906     
   2.83203125000000      -0.537964470887115     
   2.92968750000000      -0.530721834409276     
   3.02734375000000      -0.522150927843818     
   3.12500000000000      -0.512436786265136     
   3.22265625000000      -0.501747552410168     
   3.32031250000000      -0.490236961648138     
   3.41796875000000      -0.478046512570940     
   3.51562500000000      -0.465307507703403     
   3.61328125000000      -0.452142758785914     
   3.71093750000000      -0.438668278702490     
   3.80859375000000      -0.424994625544276     
   3.90625000000000      -0.411228394904050     
   4.00390625000000      -0.397473277288847     
   4.10156250000000      -0.383831372110201     
   4.19921875000000      -0.370403910478473     
   4.29687500000000      -0.357292281706303     
   4.39453125000000      -0.344598174399981     
   4.49218750000000      -0.332423974672431     
   4.58984375000000      -0.320871802060817     
   4.68750000000000      -0.310042639379781     
...



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