\documentclass{article}
\usepackage{com.braju.graphicalmodels}

\catcode`\@=11%

\pagestyle{empty}

\begin{document}
\TeXtoEPS

\LARGE
\psset{unit=10mm,arrowscale=1.5,linewidth=1.5pt}
\begin{pspicture}(0,0)(6,8)%\showgrid
  \SpecialCoor

  \rput(1,1){\GM@node[observed=true]{x1}} \GM@label[angle=-90]{x1}{$x_1$}
  \rput(3,1){\GM@node[observed=true]{x2}} \GM@label[angle=-90]{x2}{$x_2$}
  \rput(5,1){\GM@node[observed=true]{x3}} \GM@label[angle=-90]{x3}{$x_3$}

  \rput(1,3){\GM@node[observed=false]{z31}} \GM@label[angle=-45]{z31}{$z_{3,1}$}
  \rput(3,3){\GM@node[observed=false]{z32}} \GM@label[angle=-45]{z32}{$z_{3,2}$}
  \rput(5,3){\GM@node[observed=false]{z33}} \GM@label[angle=-45]{z33}{$z_{3,3}$}

  \rput(1,5){\GM@node[observed=false]{z21}} \GM@label[angle=-45]{z21}{$z_{2,1}$}
  \rput(3,5){\GM@node[observed=false]{z22}} \GM@label[angle=-45]{z22}{$z_{2,2}$}
  \rput(5,5){\GM@node[observed=false]{z23}} \GM@label[angle=-45]{z23}{$z_{2,3}$}

  \rput(1,7){\GM@node[observed=false]{z11}} \GM@label[angle=-45]{z11}{$z_{1,1}$}
  \rput(3,7){\GM@node[observed=false]{z12}} \GM@label[angle=-45]{z12}{$z_{1,2}$}
  \rput(5,7){\GM@node[observed=false]{z13}} \GM@label[angle=-45]{z13}{$z_{1,3}$}

  \ncarc[arcangle=-45]{->}{z11}{x1}
  \ncarc[arcangle=-45]{->}{z21}{x1}
  \ncarc[arcangle=-45]{->}{z31}{x1}

  \ncarc[arcangle=-45]{->}{z12}{x2}
  \ncarc[arcangle=-45]{->}{z22}{x2}
  \ncarc[arcangle=-45]{->}{z32}{x2}

  \ncarc[arcangle=-45]{->}{z13}{x3}
  \ncarc[arcangle=-45]{->}{z23}{x3}
  \ncarc[arcangle=-45]{->}{z33}{x3}

  \ncline[arrows=->]{z11}{z12}
  \ncline[arrows=->]{z12}{z13}

  \ncline[arrows=->]{z21}{z22}
  \ncline[arrows=->]{z22}{z23}

  \ncline[arrows=->]{z31}{z32}
  \ncline[arrows=->]{z32}{z33}

\end{pspicture}

\endTeXtoEPS
\end{document}
