Struct RootProblem 

pub struct RootProblem {
    pub lo: f64,
    pub hi: f64,
    pub guess: f64,
}

One bracketed root problem: an interval believed to contain a root, plus an optional starting iterate for the Newton solver.

Fields and valid ranges

• lo, hi — the bracket. Both must be finite. They may be given in either order; the solvers do not require lo < hi. The residual must have opposite signs at the two ends (or be exactly zero at one of them), otherwise the lane reports RootStatus::NotBracketed rather than guessing.
• guess — the initial iterate for solve_newton_batch. Ignored by solve_bracketed_batch, which is driven entirely by the bracket. A non-finite guess, or one outside [lo, hi], is replaced by the bracket midpoint rather than rejected — a bad guess is a performance problem, not a correctness one, because the Newton solver is bracket-safeguarded.

Units

Dimensionless f64 in whatever units the caller’s abscissa carries — kelvin for a temperature inversion, dimensionless for a compressibility factor. See the module-level “Units” section.

Example

use outram_foam_basic_lib::math::parallel::RootProblem;

// Bracket only; the Newton guess defaults to the midpoint.
let p = RootProblem::new(300.0, 3000.0);
assert_eq!(p.guess, 1650.0);

// Or seed Newton from the previous timestep's answer.
let q = RootProblem::with_guess(300.0, 3000.0, 812.5);
assert_eq!(q.guess, 812.5);

Fields

lo: f64

One end of the bracket. Finite; need not be less than hi.

hi: f64

The other end of the bracket. Finite; need not be greater than lo.

guess: f64

Starting iterate for solve_newton_batch; ignored by solve_bracketed_batch.

Implementations

impl RootProblem

pub fn new(lo: f64, hi: f64) -> Self

A problem bracketed on [lo, hi], with the Newton guess set to the bracket midpoint.

Arguments

• lo, hi — the bracket ends, finite, in either order.

pub fn with_guess(lo: f64, hi: f64, guess: f64) -> Self

A problem bracketed on [lo, hi] with an explicit Newton starting iterate.

Seeding from the previous timestep’s converged value is the usual reason to reach for this: it typically halves the iteration count of a per-cell thermodynamic inversion.

Arguments

• lo, hi — the bracket ends, finite, in either order.
• guess — starting iterate. Silently replaced by the midpoint if it is non-finite or outside the bracket.

Trait Implementations

impl Clone for RootProblem

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for RootProblem

impl Debug for RootProblem

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

Formats the value using the given formatter.

impl PartialEq for RootProblem

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for RootProblem