Struct BackgroundConfig 

pub struct BackgroundConfig {
    pub anorm_init: f64,
    pub back_a_init: f64,
    pub back_b_init: f64,
    pub back_c_init: f64,
    pub back_d_init: f64,
    pub back_f_init: f64,
    pub fit_anorm: bool,
    pub fit_back_a: bool,
    pub fit_back_b: bool,
    pub fit_back_c: bool,
    pub fit_back_d: bool,
    pub fit_back_f: bool,
}

SAMMY-style normalization and background configuration.

When enabled, the transmission model becomes: T_out(E) = Anorm × T_inner(E) + BackA + BackB / √E + BackC × √E + BackD × exp(−BackF / √E)

The first 4 background parameters (Anorm, BackA, BackB, BackC) are always available. The exponential tail (BackD, BackF) is optional and disabled by default (fit_back_d = false, fit_back_f = false).

SAMMY Reference

SAMMY manual Sec III.E.2 — NORMAlization and BACKGround cards. SAMMY fits up to 6 background terms; we implement all 6.

Fields

anorm_init: f64

Initial value for the normalization factor (default 1.0).

back_a_init: f64

Initial value for the constant background (default 0.0).

back_b_init: f64

Initial value for the 1/√E background term (default 0.0).

back_c_init: f64

Initial value for the √E background term (default 0.0).

back_d_init: f64

Initial value for the exponential amplitude (default 0.01).

Must be > 0 when fit_back_f is true, otherwise the Jacobian column for BackF is identically zero and BackF cannot be learned.

back_f_init: f64

Initial value for the exponential decay constant (default 1.0).

Units: √eV. Must be > 0 when fit_back_d is true, otherwise BackD is indistinguishable from BackA (both become constants).

fit_anorm: bool

Whether Anorm is free (true) or fixed (false).

fit_back_a: bool

Whether BackA is free (true) or fixed (false).

fit_back_b: bool

Whether BackB is free (true) or fixed (false).

fit_back_c: bool

Whether BackC is free (true) or fixed (false).

fit_back_d: bool

Whether BackD (exponential amplitude) is free (true) or fixed (false).

fit_back_f: bool

Whether BackF (exponential decay constant) is free (true) or fixed (false).

Trait Implementations

impl Clone for BackgroundConfig

fn clone(&self) -> BackgroundConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BackgroundConfig

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

Formats the value using the given formatter.

impl Default for BackgroundConfig

fn default() -> Self

Returns the “default value” for a type.