RE: Parametric Plot
- To: mathgroup at smc.vnet.net
- Subject: [mg27121] RE: [mg27077] Parametric Plot
- From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.de>
- Date: Sun, 4 Feb 2001 02:58:56 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
-----Original Message----- From: Winston Garira [mailto:uceswga at ucl.ac.uk] To: mathgroup at smc.vnet.net Subject: [mg27121] [mg27077] Parametric Plot I am trying to solve a system of two coupled pendulums using the NDSolve. command. If I replace the Plot[{xd[t],xr[t]},{t,0,100}] with ParametricPlot[{xd[t],xr[t]},{t,0,100}] it does not work. Can someone tell me why the ParametricPlot command does not work in this case. I need to make parametric plots for this system. Thanking you in annticipation Winston Pends[init1_, init2_, time_, k_, {c_, w_, p_}]:= Module[{}, pend=NDSolve[{x1''[t]+ c x1'[t]+ p Sin[x1[t]]==k(x2[t]-x1[t]), x2''[t]+ c x2'[t]+ p Sin[x2[t]]==k(x1[t]-x2[t]), x1[0]==init1[[1]], x1'[0]==init1[[2]], x2[0]==init2[[1]], x2'[0]==init2[[2]]}, {x1, x2}, {t,0,time}, MaxSteps->200000]; xd[t_] := Evaluate[x1[t] /. pend]; xdd[t_]:= Evaluate[x1'[t] /. pend]; xr[t_] := Evaluate[x2[t] /. pend]; xrd[t_]:= Evaluate[x2'[t] /. pend]; ]; c=0.1; w=0.5; p=1.9; Pends[{1.57,0}, {-1.57,0}, 5000,0.6, {c,w,p}]; Plot[{xd[t],xr[t]},{t,0,100}, PlotStyle\[Rule]{RGBColor[1,0,0.3],RGBColor[0,0.5,1]}]; W.GARIRA E-mail: w.garira at ucl.ac.uk phone : +44-(0)20-7679-2521 ___________________________________________________ Dear Winston, the problem is that your interpolating functions don't return a real, but a list containing a real. So ParametricPlot[Join[xd[t], xr[t + Pi/2]], {t, 0, 100}, Compiled -> False]; might be something more to your like. -- Hartmut Wolf