RE: plotting with boundary conditions
- To: mathgroup at smc.vnet.net
- Subject: [mg34520] RE: [mg34482] plotting with boundary conditions
- From: "Annetts, Dave (E&M, North Ryde)" <David.Annetts at csiro.au>
- Date: Fri, 24 May 2002 02:42:39 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi Raj,
to plot a surface
> f(a,b) = a^2-2*c(a,b)+b^2; given the boundary conditions c(a,b)< ab
>
> Here c(a,b) is another function of (a,b) given by
> c(a,b) = 0.1*(a-1)^2+0.1*(b-1)^2-0.01
>
> Is there a direct command to set these boundary
> conditions...?? If i give
>
> f[a_, b_] := If[c[a, b] < a*b, a^2 + b^2 - 2*c[a, b],];
>
> Plot3D[f[a, b], {a, 0, 2}, {b, 0, 2}, AxesLabel -> {"a", "b", "f"},
> ViewPoint -> {2, 2, 2}]
>
> I get error messages for the values of a and b for which
> f(a,b) doesnot exist.
>
> Can anybody please tell me how i can get this plot?
After defining your function c, it works fine ...
c[a_, b_] := 0.1*(a-1)^2+0.1*(b-1)^2-0.01
f[a_,b_]:=If[c[a,b]<a*b,a^2+b^2-2*c[a,b],Null];
Plot3D[f[a,b],{a,0,2},{b,0,2},AxesLabel\[Rule]{"a","b","f"},
ViewPoint\[Rule]{2,2,2}];
You can supress the warnings by setting
Off[Plot3D::plnc];
Off[Plot3D::gval];
Regards,
Dave.
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Dr. David Annetts EM Modelling Analyst
Tel: (+612) 9490 5416 CSIRO DEM, North Ryde
Fax: (+612) 9490 5467 David.Annetts at csiro.au
Include "usual_disclaimers"
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