Enum EnergyScaleJacobianMethod 

pub enum EnergyScaleJacobianMethod {
    FiniteDifference,
    PartialGal,
}

Method for computing the t0 / L_scale columns of the EnergyScaleTransmissionModel Jacobian.

• PartialGal (default since issue #489): central FD on t0 only (2 evaluations); derive L_scale column inline via the rank-1 identity J[:, L_scale] = ((tof - t0) / L_scale) * J[:, t0] per energy bin. Halves the FD probe count on workloads where both calibration parameters are free.

  Correctness regime: exact in the no-resolution limit and the narrow-kernel limit. With a non-trivial resolution operator R, the rank-1 simplification additionally assumes per-bin uniformity of (tof - t0) / L_scale over the kernel support — necessary because R mixes source bins whose ratios differ. broaden_presorted uses self.flight_path_m (not the model’s L_nominal * L_scale) so tabulated kernels satisfy the structural factorisation through e_corr, but the per-bin homogeneity assumption is empirical. On real VENUS Hf 120-min KL+per-iso+TZERO 4×4 the approximation is tight enough that 15/16 pixels converge within 0.1·σ_Fisher of FD2; median wall-time speedup 1.28× over FD2.

• FiniteDifference: central FD on the full inner forward chain, 4 forward evaluations per Jacobian (h_t0=1e-4, h_ls=1e-7). The pre-#489 production default; reachable via NEREIDS_TZERO_JACOBIAN=fd2 env var or tzero_jacobian="fd2" Python kwarg.

Variants

FiniteDifference

PartialGal

Trait Implementations

impl Clone for EnergyScaleJacobianMethod

fn clone(&self) -> EnergyScaleJacobianMethod

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for EnergyScaleJacobianMethod

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for EnergyScaleJacobianMethod

fn eq(&self, other: &EnergyScaleJacobianMethod) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for EnergyScaleJacobianMethod

impl Eq for EnergyScaleJacobianMethod

impl StructuralPartialEq for EnergyScaleJacobianMethod