# [pstricks] using the xylogscale of pst-plot vs gnuplot exponent issue

Herbert Voss Herbert.Voss at FU-Berlin.DE
Wed Mar 12 10:54:45 CET 2014

Am 10.03.2014 21:32, schrieb Julien Morand:

> http://commons.wikimedia.org/wiki/File:Bv_rdson.png
>
> I try to use the psgraph environment of pst-plot but when I write the
> given equation the plot is not correct. I have to modify the value of
> the exponent from 2.5 to 320!!
>
> I also try the same equation using gnuplot and the plot is correct (see
> attached files). Is there anyone that could help me on with this issue?
> here is my code:

you used a x value in the intervall {1.69879}{3.301} but it must be
{10^1.69879}{10^3.301}

\documentclass[pstricks]{standalone}

\begin{document}
\psset{xAxisLabel=$V_{br}(V)$,
yAxisLabel=$\displaystyle R_{sp\acute{e}cifique}\left(\frac{\Omega}{cm^2} \right)$,
llx=-1.5cm,lly=-1cm,urx=1.5cm,ury=1.5cm}
\begin{psgraph}[tickcolor=lightgray,subtickcolor=lightgray,subticksize=0.5,
Ox=1,Dx=1,xsubticks=9,xylogBase=10,
logLines=all,Oy=-4,Dy=1,
ysubticks=9] {->}(1,-4)(3.301,1.18){11cm}{6cm}
\psplot[linecolor=darkgray,linestyle=dashed]{1.69879}{3.301}{5.93e-9 320
x exp mul log}
\psplot[linecolor=green,algebraic]{1.69879}{3.301}{ log(
5.93e-9*(10^x)^2.5 )}
\end{psgraph}

\end{document}

Herbert