desc.integrals.Bounce2D.interp_to_argmin

Bounce2D.interp_to_argmin(f, points, *, nufft_eps=-1.0, **kwargs)Source

Interpolate f to the deepest point in magnetic well w.

Interpolate f to the argmin of the magnetic field between each pair in points. Explicitly, let E(w) = {ζ ∣ ζ₁(w) < ζ < ζ₂(w)} and A(w) ∈ argmin_E(w) B. Returns {f ∘ A(w)}.

Parameters:

  • f (jnp.ndarray) – Shape (num ρ, num ζ, num θ). Real scalar-valued periodic function in (θ, ζ) ∈ [0, 2π) × [0, 2π/NFP) evaluated on the grid supplied to construct this object. Use the method Bounce2D.reshape to reshape the data into the expected shape. If the input is not a real-valued array, then it is assumed that the Fourier transform as returned by Bounce2D.fourier was given instead.

  • points (tuple[jnp.ndarray]) – Shape (num ρ, num α, num pitch, num well). Optional, output of method self.points. Tuple of length two (z1, z2) that stores ζ coordinates of bounce points. The points are ordered and grouped such that the straight line path between z1 and z2 resides in the epigraph of B.

  • nufft_eps (float) – Precision requested for interpolation with non-uniform fast Fourier transform (NUFFT). If less than 1e-14 then NUFFT will not be used.

Returns:

f_j (jnp.ndarray) – Shape (num ρ, num α, num pitch, num well). f interpolated to the deepest point between points.