title: Trouble fitting small values with gnuplot
body: <p>I'll try to explain what I'm doing and show the error I'm getting at the end. So, I have a file with the following data:</p>
  
  <pre><code>1.00000000E-05  8.39843750E-02  1.28074971E-02
  1.00000000E-06  6.83593750E-02  1.15548433E-02
  1.00000000E-07  4.29687500E-02  9.16096828E-03
  1.00000000E-08  2.73437500E-02  7.30792458E-03
  1.00000000E-09  3.90625000E-02  8.73464054E-03
  1.00000000E-10  2.34375000E-02  6.76582347E-03
  1.00000000E-11  1.36718750E-02  5.16748303E-03
  1.00000000E-12  1.56250000E-02  5.52427173E-03
  </code></pre>
  
  <p>and I need to do a fitting. I do it with</p>
  
  <pre><code>datfile = "data.dat"
  a = 0.1; b = 0.2
  f(x) = a*x**b
  fit f(x) datfile u 1:2:3 yerrors via a, b
  </code></pre>
  
  <p>and obtain the values <code>a = 0.312672</code> and <code>b=0.116722</code>. Then I want to plot the points and the fitting function. But the fitting function gets "fractured" at <code>x = 10^-9</code> as you can see here-><a href="https://i.stack.imgur.com/fNRJ8.png" rel="nofollow noreferrer">1</a>. I believe there may be something to do with the numerical precision, but couldn't figure out. My version of gnuplot is <code>5.2</code> and my code for plotting is</p>
  
  <pre><code>set logscale x
  set logscale y
  plot datfile u 1:2:3 w yerrorbars, f(x) w lines lw 2
  </code></pre>
  
  <p>Thanks in advance!</p>