Enum CantForm 

#[non_exhaustive]
pub enum CantForm {
    Polynomial {
        coefficients: Vec<f64>,
    },
    Cosine {
        start: f64,
        change: f64,
    },
    Sine {
        start: f64,
        change: f64,
    },
    VienneseBend {
        start: f64,
        change: f64,
    },
    AboutRail {
        rail: RailSide,
        elevation: f64,
    },
}

The shape of one cant piece over its own xi = s / length in [0, 1].

Height forms give the cant D (the left rail head above the right) in length units; the angle form gives the bank angle psi in radians.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Polynomial

D(xi) = coefficients[0] + coefficients[1] xi + coefficients[2] xi^2 + ...

Covers a constant cant (degree 0), a linear transition (degree 1), the Bloss transition D1 + dD (3 - 2 xi) xi^2 (degree 3) and each half of a Helmert transition (degree 2; see CantPiece::helmert). An empty list is zero.

Fields

coefficients: Vec<f64>

Coefficients in ascending powers of xi.

Cosine

D(xi) = start + change (1 - cos(pi xi)) / 2: the half-cosine transition, tangent to its neighbours’ slopes at both ends.

Fields

start: f64

Cant at xi = 0.

change: f64

Cant gained over the piece.

Sine

D(xi) = start + change (xi - sin(2 pi xi) / (2 pi)): the sine transition, whose slope AND curvature vanish at both ends.

Fields

start: f64

Cant at xi = 0.

change: f64

Cant gained over the piece.

VienneseBend

psi(xi) = start + change xi^4 (35 - 84 xi + 70 xi^2 - 20 xi^3): the Viennese bend, written for the bank angle itself. Its first three derivatives vanish at both ends. The cant follows as b sin(psi).

Fields

start: f64

Bank angle at xi = 0, radians.

change: f64

Bank angle gained over the piece, radians.

AboutRail

A pivot piece rotating about the held rail (#279): e = elevation + s (b / 2) sin(psi) = elevation + s D / 2, D and psi the cant law’s at the same plan distance, s = +1 about the right rail and -1 about the left. See the module docs.

Derived, not a law of xi: CantLaw::value_at has no value for it and Banked3::pivot_at reads it. Refused in a cant law.

Fields

rail: RailSide

The rail head that keeps its height.

elevation: f64

Height e0 of the held rail head above the profile.

Trait Implementations

impl Clone for CantForm

fn clone(&self) -> CantForm

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CantForm

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CantForm

fn deserialize<__D>( __deserializer: __D, ) -> Result<CantForm, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for CantForm

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for CantForm

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for CantForm