[pstricks] re-using the same random variable

[Herbert Voss]

jmpapy wrote:

> Maybe I don't understand how the postscript language works in this case.
> To me, each time the program read "rand", it returns a new integer 
> randomly drawn from [0 2^31 -1]. Is it correct ? 

sure, but we always call the value of the intervall -5..5 the
x-value. However no problem.
Next try, the second example shows rand/2 to see that it is
exactly the same list of random numbers.


Herbert


\documentclass{article}
\usepackage{pstricks,pstricks-add}

\begin{document}

\pstVerb{
   /randReal { rand 2147483647 div } def
   rrand srand
}
\psset{yunit=3cm}
\begin{pspicture}(-5,-0.2)(5,1.5)
\psaxes(0,0)(-5,0)(5,1)
\psplot[linecolor=red,plotpoints=200,showpoints=true,linestyle=none]{-5}
     {5}{ randReal dup 2.72 exp mul } %x.e^{x}
\end{pspicture}

\psset{yunit=1cm}
\begin{pspicture}(-5,-0.2)(5,7)
   \psaxes(0,0)(-5,0)(5,6)
   \psset{plotpoints=20,linestyle=dotted,linewidth=2pt}
   \pstVerb{  987654321 srand }
   \psplot[linecolor=red]{-5}{5}{ randReal 6 mul } % x
   \pstVerb{ 987654321 srand }
   \psplot[linecolor=blue]{-5}{5}{ randReal 6 mul 2 div } % x2
\end{pspicture}

\end{document}




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