# [pstricks] \psplotDiffEqn initial conditions using \multido

Hernando Diaz hdiazmo at unal.edu.co
Fri Jun 23 19:16:31 CEST 2006

Hi:
I am trying to generate  phase portraits of  differential equations using
\psplotDiffEqn. I would like to specify different initial conditions using a
\multido environment. I have tried Number (\N) and real (\R) variables
without success. Is there a way to do it?

Below, I include a small example of what I want

Hernando Diaz

\documentclass{minimal}
\begin{document}
\def\Func{y[1]|0.5*y[1]-y[0]-y[1]^3}
\psset{unit=2cm,algebraic=true,linewidth=0.5pt}
\begin {pspicture}(-3,-3)(3,3)%\psgrid[subgriddiv=2,griddots=10]
\psframe(-3,-3)(3,3)
\psset{method=rk4,plotpoints=400,linecolor=blue,linewidth=0.5pt}
\psset{whichabs=0,whichord=1}
%\multido{\r=-1.5+1.5}{3}{
\psplotDiffEqn{0}{30}{-1.5 -3}{\Func}
\psplotDiffEqn{0}{30}{0 -3}{\Func}
\psplotDiffEqn{0}{30}{1.5 -3}{\Func}
\psplotDiffEqn{0}{30}{-1.5 3}{\Func}
\psplotDiffEqn{0}{30}{0 3}{\Func}
\psplotDiffEqn{0}{30}{1.5 3}{\Func}
%}
\psplotDiffEqn[whichabs=0,whichord=1]{0}{30}{0.01 0.01}{\Func}
\end{pspicture}
\end{document}