I have the following function:
L[n_, t_] := Abs[2/Pi*(2 n - 1)!!^2/((2 n)! (2 n - 1)^2) *
HypergeometricPFQ[{3/2, 1/2 - n, 1/2 - n}, {3/2 - n, 3/2 - n}, Exp[-2 I*t]]]^2
If I now plot this function, let's say:
Plot[L[n, t], {t, 0, Pi/2}, PerformanceGoal -> "Speed"]
Then, very "smooth" results are yielded until n=16. For n>16, the plot becomes really oscillatory, which seems weird to me.
I wonder whether this is a numeric problem and how to find out whether it is? I evaluated some values with high precision and they seem to agree with the plot... This is what I tested, for example:
Lo[N[17, 200], N[0.273, 100]]=0.
WorkingPrecision->20
to thePlot
. Raise the setting as needed to address any observed instabilities. $\endgroup$ – QuantumDot Jul 20 '17 at 13:35