[pstricks] Two fail --- Backward solution?

[David Arnold]

Hernando et al,

That didn't work:

-------------- next part --------------
A non-text attachment was scrubbed...
Name: pastedGraphic.tiff
Type: image/tiff
Size: 12718 bytes
Desc: not available
Url : http://tug.org/pipermail/pstricks/attachments/20090206/2d790562/attachment.tiff 
-------------- next part --------------


What I want to do is extend the solution with initial condition -0.5  
backward in time.

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

\begin{document}

\def\Funct{dup 3 exp exch sub}\def\negFunct{dup 3 exp exch sub neg}
\psset{unit=2cm,arrowscale=2}
\begin{center}
\begin{pspicture}(-2,-2)(2,2)
	\psaxes[labels=none,ticksize=0 0pt]{<->}(0,0)(-2,-2)(2,2)[$t$,0][$y$,0]
	\psline[linecolor=blue,linewidth=1pt]{<->}(-2,-1)(2,-1)
	\psline[linecolor=blue,linewidth=1pt]{<->}(-2,0)(2,0)
	\psline[linecolor=blue,linewidth=1pt]{<->}(-2,1)(2,1)
	\psplotDiffEqn[linecolor=black,method=varrkiv,varsteptol=0.0001]{0} 
{2}{-1.5}{\Funct}
	\psplotDiffEqn[linecolor=black,method=varrkiv,varsteptol=0.0001]{0} 
{2}{-0.5}{\Funct}
	\psplotDiffEqn[linecolor=black,method=varrkiv,varsteptol=0.0001]{0} 
{2}{-0.5}{\negFunct}
	\psplotDiffEqn[linecolor=black,method=varrkiv,varsteptol=0.0001]{0} 
{2}{0.5}{\Funct}
	\psplotDiffEqn[linecolor=black,method=varrkiv,varsteptol=0.0001]{0} 
{2}{1.5}{\Funct}
	\uput[l](-2,1){$y=1$}
	\uput[l](-2,0){$y=0$}
	\uput[l](-2,-1){$y=-1$}
	\pscircle[fillstyle=solid,fillcolor=white,linecolor=blue](0,1){3pt}
	\pscircle[fillstyle=solid,fillcolor=blue,linecolor=blue](0,0){3pt}
	\pscircle[fillstyle=solid,fillcolor=white,linecolor=blue](0,-1){3pt}
	\psset{arrowscale=1}
	\psline[linecolor=red,linewidth=3pt]{->}(0,1.3)(0,1.7)
	\psline[linecolor=red,linewidth=3pt]{<-}(0,0.3)(0,0.7)	
	\psline[linecolor=red,linewidth=3pt]{->}(0,-0.7)(0,-0.3)
	\psline[linecolor=red,linewidth=3pt]{->}(0,-1.3)(0,-1.7)
\end{pspicture}
\end{center}


\end{document}


David.
On Feb 6, 2009, at 5:42 AM, Hernando Diaz wrote:

David Arnold escribi?:
> All,
>
> I'm wondering why my initial conditions at -1.5 and 1.5 fail to draw
> in the code below. Also, I am looking for a way to do solutions
> backward in time.
>
Hi David:
How about using

\def\negFunct{dup 3 exp exch sub neg}

and then solving

\psplotDiffEqn[linecolor=black,method=varrkiv,varsteptol=0.0001]{0}
{2}{SomeSuitableInitialcondition}{\negFunct}
?

Best regards,
Hernando Diaz



_______________________________________________
PSTricks mailing list
PSTricks at tug.org
http://tug.org/mailman/listinfo/pstricks