Enum Term 

pub enum Term {
    Intercept,
    Numeric(String),
    Factor {
        name: String,
        reference: Option<String>,
    },
    Interaction {
        a: String,
        b: String,
    },
    Poly {
        name: String,
        degree: usize,
    },
    Hinges {
        name: String,
        knots: Vec<f64>,
    },
    Steps {
        name: String,
        knots: Vec<f64>,
    },
    Bins {
        name: String,
        cuts: Vec<f64>,
        reference: Option<usize>,
    },
    Log {
        name: String,
        base: f64,
    },
    Ordinal {
        name: String,
        levels: Vec<String>,
    },
    OrthogonalPoly {
        name: String,
        degree: usize,
    },
    NaturalSpline {
        name: String,
        knots: Vec<f64>,
        boundary: Option<(f64, f64)>,
    },
}

One term of a model formula.

Variants

Intercept

A column of ones.

Numeric(String)

A numeric column, as is.

Factor

A categorical column in treatment coding: one indicator column per level except the reference. The reference is the given level, or the first in sorted order (R’s and statsmodels’ default).

Fields

name: String

reference: Option<String>

Interaction

The product of two columns, each numeric as is or a factor in treatment coding with its first level as reference: a:b, a[x]:b or a[x]:b[y], R’s a:b beside main effects.

Fields

a: String

b: String

Poly

Raw powers x, x², …, x^degree of a numeric column, named x, x^2, ….

Fields

name: String

degree: usize

Hinges

Hinge functions max(0, x − k) at each knot, named hinge(x,k).

Fields

name: String

knots: Vec<f64>

Steps

Steps 1[x ≥ k] at each knot, named step(x,k).

Fields

name: String

knots: Vec<f64>

Bins

A numeric column cut into bins (−∞, c₁], (c₁, c₂], …, (c_k, ∞) and coded as a factor (named as R’s cut, x[(30,45]]), the bin with index reference (default 0, the lowest) as reference.

Fields

name: String

cuts: Vec<f64>

reference: Option<usize>

Log

ln(x / base), named log(x/base): a log transform centred so a coefficient’s base value is base (CAS Monograph 5, section 5.6.2).

Fields

name: String

base: f64

Ordinal

An ordered factor in cumulative coding: for each level after the first in levels’ order, 1[level ≥ it], named x[>=level]. Each coefficient is the step from the level below.

Fields

name: String

levels: Vec<String>

OrthogonalPoly

Orthogonal polynomials of degree 1 to degree on the training values, as R’s poly(x, degree), named poly(x)1, poly(x)2, …. The recurrence learned in training rebuilds them on new data.

Fields

name: String

degree: usize

NaturalSpline

A natural cubic spline with interior knots, linear beyond the boundary knots (the training range unless given): knots.len() + 1 columns named spline(x)1, …. The basis is the restricted cubic (truncated power) one, which spans the same functions as R’s splines::ns(x, knots): fitted values agree, coefficients differ.

Fields

name: String

knots: Vec<f64>

boundary: Option<(f64, f64)>

Trait Implementations

impl Clone for Term

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Term

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

Formats the value using the given formatter.

impl PartialEq for Term

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Term