Struct

`space::irbem::IrbemFaithful`

cheatah-space v0.1.0-alpha — Biome Standard 0.6.5-alpha

Reproduce IRBEM's algorithm, decision for decision — every switch off.

This is the lane the differential suite runs when it compares against the oracle, because a comparison is only informative when both sides discretize the same way: ERROR_BUDGET §2(a) shows the 0.01 L* target is at or below IRBEM's own error at its recommended resolution, so a comparison across settings measures resolution rather than correctness. Not the lane to ship.

Constants & variables

var static bool carry_k1 #

Off — the field is evaluated a fifth time at each step's arrival point, and that value is discarded rather than reused as the next step's first stage.

The redundancy is arithmetically invisible (the same function of the same bits gives the same bits), so this switch is about the call sequence, not the numbers: a faithful lane calls the field model the same number of times in the same order, which matters while cross-checking against a library whose field models carry mutable COMMON state.

var static bool independent_azimuth_seed #

Off — the drift shell's azimuths are walked in sequence, each seeded from the previous azimuth's converged result.

Correct, and serial: the shell's ~25·(options(4)+1) azimuths cannot be evaluated concurrently, and the answer depends on the order they were visited in.

var static bool bracketed_root_find #

Off — the mirror point is the θ-grid point at which the field crosses Bm, on the fixed grid dθ = π/(720·(options(3)+1)).

The located root therefore carries O(dθ) error that jitters as the grid changes, which is the non-monotonic convergence measured in ERROR_BUDGET §2(b) (options=4 repeatedly worse than options=2).

var static bool transformed_quadrature #

Off — the I integral ∫ √(1 − B/Bm) ds between mirror points (Roederer, Dynamics of Geomagnetically Trapped Radiation, 1970, §2) is summed as first-order rectangles on the θ grid.

The integrand's derivative is singular at both endpoints, where B → Bm, so the rectangle rule converges at O(h) with a large endpoint constant. ERROR_BUDGET §2(b) names this the single largest accuracy lever in the original algorithm.

var static std::string_view name #

Human-readable lane name, for the differential suite's per-lane report.