I'm not sure why nothing appears and no warning or error is raised. It
may have to do with the type of v[1]. Try this:
{{{
M = matrix(3,[1,-1,-1,-1,3,1,-1,1,3]); v=M.eigenvalues();
x,y,z = var('x,y,z')
Q=implicit_plot3d(x^2+y^2+z^2==RDF(1/v[1]), [x,-3,3], [y,-3,3],
[z,-3,3], opacity=0.5); Q
}}}
I see a sphere. Changing 1/v[1] to RDF(1/v[1]) coerces 1/v[1] into the
field of real numbers RDF.
On Jan 6, 11:56 am, pong <wypon...@gmail.com> wrote:
> Here are the code:
>
> M = matrix(3,[1,-1,-1,-1,3,1,-1,1,3]); v=M.eigenvalues(); v
>
> [2, 0.4384471871911698?, 4.561552812808830?]
>
> Q=implicit_plot3d(x^2+y^2+z^2==1/v[1], [x,-3,3], [y,-3,3],[z,-3,3],
> opacity=0.5); Q
>
> Jmol shows nothing. However, if I change 1/v[1] to 2.28 (~1/v[1]) then
> it shows the sphere.
>
> Any idea why?
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