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Topic: ParametricPlot Remark
Replies: 0

 Andrei Constantinescu Posts: 32 Registered: 12/7/04
ParametricPlot Remark
Posted: May 14, 1997 1:09 AM

Hellow !

... so I just remarked a pretty unusual thing with ParametricPlot / 3D ,
and theirs Automatic PlotPoints number !

So lets resume:

ParametricPlot - works fine giving nice smooth courbes ,

wether

ParametricPlot3D - samples largely giving a pretty zigzag form !

SURE , I can be fitted by hand, ... and I did it ! But does someone
understand why this happens ?

You have bellow a sample program of the Lorenz Equations in order to
test it !

Have fun !

a + andrei

s = 10;
b = 8/3;
r = 167;

tmax = 10;

eq = {
x'[t] == s ( y[t] - x[t] ),
y'[t] == r x[t] - y[t] - x[t] z[t],
z'[t] == - b z[t] + x[t] y[t],
x[0] == 0,
y[0] == 1,
z[0] == 0
}

sol = NDSolve[ eq, {x,y,z} , {t, 0, tmax},
MaxSteps -> 5000, StartingStepSize -> 0.001]

ParametricPlot3D[ Evaluate[{x[t], y[t], z[t]} /. sol[[1]] ], {t,0,tmax},
PlotRange -> All ]
ParametricPlot[ Evaluate[{z[t], x[t]} /. sol[[1]] ], {t,0,tmax} ,
PlotRange -> All ]
ParametricPlot[ Evaluate[{z[t], y[t]} /. sol[[1]] ], {t,0,tmax} ,
PlotRange -> All ]
ParametricPlot[ Evaluate[{x[t], y[t]} /. sol[[1]] ], {t,0,tmax} ,
PlotRange -> All ]

______________________________________________________________________
Andrei Constantinescu constant@athena.polytechnique.fr

LMS Ecole Polytechnique tel: (33)-1-69.33.33.30
91128 PALAISEAU cedex - FRANCE fax: (33)-1-69.33.30.26