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BlackHolePerturbationToolkit / KerrGeodesics

Code to compute quantities related to bound timelike Kerr geodesics
MIT License
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Error for KerrGeoOrbit when a=0 #45

Open VojtechW opened 1 year ago

VojtechW commented 1 year ago

It seems that the analytical method for KerrGeoOrbit returns expressions that are not manifestly real for $a=0$.

MWE: orbit = KerrGeoOrbit[0, 20, 0.9, Cos[\[Pi]/8]]; {t, r, \[Theta], \[CurlyPhi]} = orbit["Trajectory"]; Show[ParametricPlot3D[{r[\[Lambda]] Sin[\[Theta][\[Lambda]]] Cos[\ \[CurlyPhi][\[Lambda]]], r[\[Lambda]] Sin[\[Theta][\[Lambda]]] Sin[\[CurlyPhi][\[Lambda]]], r[\[Lambda]] Cos[\[Theta][\[Lambda]]]}, {\[Lambda], 0, 20}, ImageSize -> 700, Boxed -> False, Axes -> False, PlotStyle -> Red, PlotRange -> All], Graphics3D[{Black, Sphere[{0, 0, 0}, 2]}]]

Returns

obrazek

This appears for any $p,e,x$ at $a=0$.

nielsw2 commented 1 year ago

I am not sure why this error appears as the trajectory evaluates just fine and the plot also works. The error message only appears with ParametricPlot3D, and does not appear if you instead use a Table.