I’m not sure what the correct syntax is (got some StackOverflowErrors) for getting the hessian of a parametric spline in Interpolations.jl.
So from the docs:
using Interpolations
t = 0:.1:1
x = sin.(2π*t)
y = cos.(2π*t)
A = hcat(x,y)
itp = Interpolations.scale(interpolate(A, (BSpline(Cubic(Natural(OnGrid()))), NoInterp())), t, 1:2)
tfine = 0:.01:1
xs, ys = [itp(t,1) for t in tfine], [itp(t,2) for t in tfine]
How would I get the hessian for each element in, say, tfine?