Struct NonNegativeRealScalar 

pub struct NonNegativeRealScalar<RealType: RealScalar>(/* private fields */);

Type-safe wrapper for non-negative real scalar values.

NonNegativeRealScalar<T> guarantees that wrapped values are greater than or equal to zero. Zero is valid for this type. For values that must be strictly positive, use PositiveRealScalar.

Mathematical Definition

NonNegativeRealScalar<T> = { x ∈ T : x ≥ 0 }

This is the set of non-negative real numbers ℝ₀⁺, which includes zero.

Use Cases

• Distances (can be zero when comparing a value to itself)
• Absolute values
• Magnitudes
• Any quantity that is mathematically required to be ≥ 0

Examples

Basic Usage

use num_valid::scalars::{NonNegativeRealScalar, ErrorsNonNegativeRealScalar};
use try_create::TryNew;

// Zero is valid
let zero = NonNegativeRealScalar::try_new(0.0_f64).unwrap();
assert_eq!(*zero.as_ref(), 0.0);

// Positive values are valid
let positive = NonNegativeRealScalar::try_new(5.0_f64).unwrap();

// Negative values are rejected
assert!(matches!(
    NonNegativeRealScalar::try_new(-1.0_f64),
    Err(ErrorsNonNegativeRealScalar::NegativeValue { .. })
));

Use Case: Computing Distances

use num_valid::scalars::NonNegativeRealScalar;
use try_create::TryNew;

fn distance(a: f64, b: f64) -> NonNegativeRealScalar<f64> {
    NonNegativeRealScalar::try_new((a - b).abs()).unwrap()
}

// Different points
let d1 = distance(0.0, 5.0);
assert_eq!(*d1.as_ref(), 5.0);

// Same point (zero distance is valid!)
let d2 = distance(3.0, 3.0);
assert_eq!(*d2.as_ref(), 0.0);

Algebraic and Ordering Operations

NonNegativeRealScalar supports additive composition, the Zero trait, and ordering helpers from Max and Min:

use num::Zero;
use num_valid::{
    functions::{Max, Min},
    scalars::NonNegativeRealScalar,
};
use try_create::TryNew;

let a = NonNegativeRealScalar::try_new(1.25_f64).unwrap();
let b = NonNegativeRealScalar::try_new(2.75_f64).unwrap();

// Add preserves non-negativity for valid operands.
let sum = a + b;
assert_eq!(*sum.as_ref(), 4.0);

// Zero is the additive identity.
let z = NonNegativeRealScalar::<f64>::zero();
assert!(z.is_zero());
assert_eq!(*(sum + z).as_ref(), 4.0);

let x = NonNegativeRealScalar::try_new(1.0_f64).unwrap();
let y = NonNegativeRealScalar::try_new(3.0_f64).unwrap();
assert_eq!(*Max::max_by_ref(&x, &y).as_ref(), 3.0);
assert_eq!(*Min::min_by_value(x, y).as_ref(), 1.0);

Implementations

impl<RealType: RealScalar> NonNegativeRealScalar<RealType>

pub fn into_inner(self) -> RealType

Consumes the struct and returns the inner value.

Trait Implementations

impl<RealType: RealScalar> Add for NonNegativeRealScalar<RealType>

Implements additive composition for NonNegativeRealScalar.

Since both operands are guaranteed to be non-negative, their sum is also non-negative.

type Output = NonNegativeRealScalar<RealType>

The resulting type after applying the + operator.

fn add(self, other: Self) -> Self

Performs the + operation.

impl<RealType: RealScalar> AsRef<RealType> for NonNegativeRealScalar<RealType>

fn as_ref(&self) -> &RealType

Converts this type into a shared reference of the (usually inferred) input type.

impl<RealType: Clone + RealScalar> Clone for NonNegativeRealScalar<RealType>

fn clone(&self) -> NonNegativeRealScalar<RealType>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<RealType: Debug + RealScalar> Debug for NonNegativeRealScalar<RealType>

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

Formats the value using the given formatter.

impl<'de, RealType> Deserialize<'de> for NonNegativeRealScalar<RealType>

where RealType: for<'a> Deserialize<'a> + RealScalar,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<RealType> Display for NonNegativeRealScalar<RealType>

where RealType: Display + RealScalar,

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

Formats the value using the given formatter.

impl<RealType: RealScalar> IntoInner for NonNegativeRealScalar<RealType>

fn into_inner(self) -> Self::InnerType

Consumes the struct and returns the inner value.

type InnerType = RealType

The type of the inner value that will be extracted.

impl<RealType: RealScalar> Max for NonNegativeRealScalar<RealType>

Implements Max for NonNegativeRealScalar.

Maximum selection is delegated to the default trait behavior based on PartialOrd.

fn max_by_ref<'a>(&'a self, other: &'a Self) -> &'a Self

Returns a reference to the maximum of self and other.

fn max_by_value(self, other: Self) -> Self

Returns the maximum of self and other, consuming both values.

impl<RealType: RealScalar> Min for NonNegativeRealScalar<RealType>

Implements Min for NonNegativeRealScalar.

Minimum selection is delegated to the default trait behavior based on PartialOrd.

fn min_by_ref<'a>(&'a self, other: &'a Self) -> &'a Self

Returns a reference to the minimum of self and other.

fn min_by_value(self, other: Self) -> Self

Returns the minimum of self and other, consuming both values.

impl<RealType: PartialEq + RealScalar> PartialEq for NonNegativeRealScalar<RealType>

fn eq(&self, other: &NonNegativeRealScalar<RealType>) -> 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<RealType: PartialOrd + RealScalar> PartialOrd for NonNegativeRealScalar<RealType>

fn partial_cmp( &self, other: &NonNegativeRealScalar<RealType>, ) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<RealType> Serialize for NonNegativeRealScalar<RealType>

where RealType: Serialize + RealScalar,

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<RealType: PartialEq + RealScalar> StructuralPartialEq for NonNegativeRealScalar<RealType>

impl<RealType: RealScalar> TryNew for NonNegativeRealScalar<RealType>

fn try_new(value: RealType) -> Result<Self, Self::Error>

Attempts to create a NonNegativeRealScalar from a value.

Errors

Returns ErrorsNonNegativeRealScalar::NegativeValue if the input is negative.

Panics (Debug Mode Only)

In debug builds, panics if the input is not finite (NaN or infinity).

Examples

use num_valid::scalars::{NonNegativeRealScalar, ErrorsNonNegativeRealScalar};
use try_create::TryNew;

// Zero is valid
assert!(NonNegativeRealScalar::try_new(0.0_f64).is_ok());

// Positive is valid
assert!(NonNegativeRealScalar::try_new(1.0_f64).is_ok());

// Negative is rejected
assert!(matches!(
    NonNegativeRealScalar::try_new(-1.0_f64),
    Err(ErrorsNonNegativeRealScalar::NegativeValue { .. })
));

type Error = ErrorsNonNegativeRealScalar<RealType>

The error type that can be returned by the try_new method.

impl<RealType: RealScalar> Zero for NonNegativeRealScalar<RealType>

Implements Zero for NonNegativeRealScalar.

The zero value is always valid, and acts as the additive identity.

fn is_zero(&self) -> bool

Returns true if self is equal to the additive identity.

fn zero() -> Self

Returns the additive identity element of Self, 0.

fn set_zero(&mut self)

Sets self to the additive identity element of Self, 0.