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<div> Hello,<br>
<br>
When we use the option "saveData=true" of the macro "\psplotDiffEqn" (package "pstricks-add") in a loop, it arises two strange behaviors:<br>
-  a systematic horizontal shift of the  curves.<br>
-  a downscaling  of the grid ("psgrid") and objects.<br>
<br>
Did you know these problems? Do you have a solution? <br>
<br>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
<br>
\documentclass{article}<br>
\usepackage{pstricks-add,pst-func}<br>
<br>
\def\vXvY{(v0*((y[1])^4)-wR*(Ra^2)*((y[1])^3)+2*v0*(y[0]^2)*((y[1])^2)+((y[1])^2)*v0*((Ra)^2)-wR*(Ra^2)*(y[0]^2)*(y[1])+v0*(y[0]^4)-v0*(Ra^2)*(y[0]^2))/((y[0]^2+y[1]^2)^2)<br>
|<br>
(y[0]*(Ra^2)*(wR*((y[1])^2)-2*v0*(y[1])+wR*(y[0]^2)))/((y[0]^2+y[1]^2)^2)}<br>
<br>
\begin{document}<br>
\begin{center}<br>
\begin{pspicture}(-8,-6)(8,6)%<br>
\psgrid%<br>
\psframe*[linecolor=gray!30](-8,-6)(8,6)%<br>
\pstVerb{%<br>
/v0 1 def % vitesse a l'infini m/s<br>
/Ra 1 def % rayon du cylindre<br>
/wR 2.25 def % vitesse de rotation du cylindre rd/s<br>
}%<br>
\pscircle{!Ra}<br>
\BeginSaveFinalState%<br>
\multido{\ry=-4+0.5}{22}{%<br>
\psplotDiffEqn[%<br>
    linecolor=red,%<br>
    method=rk4,%<br>
    algebraic,%<br>
    plotpoints=1000,%<br>
    saveData=true,%<br>
    filename=PSTdata\i,%<br>
    whichabs=0, whichord=1]{-8}{35}{-8 \ry}{\vXvY}%<br>
}%<br>
\EndSaveFinalState%<br>
\pscircle[fillstyle=solid,fillcolor=gray,linecolor=red]{!Ra}<br>
\psarc{->}(0,0){0.75}{240}{300}<br>
\psgrid%<br>
\end{pspicture}<br>
\end{center}<br>
\end{document}<br>
<br>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
<br>
Thanks,<br>
<br>
Manuel<br>

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