quaternion_core

Function norm

Source 
pub fn norm<T, U>(a: U) -> T
where
    T: Float,
    U: QuaternionOps<T>,
Expand description

Calculate L2 norm of Vector3 or Quaternion.

Compared to dot(a, a).sqrt(), this function is less likely to cause overflow and underflow.

When the norm-sqrt feature is enabled, the default implementation is compiled with dot(a, a).sqrt() instead.

ยงExamples

// --- Vector3 --- //
let v: Vector3<f64> = [1.0, 2.0, 3.0];
assert!( (14.0_f64.sqrt() - norm(v)).abs() < 1e-12 );
 
// --- Quaternion --- //
let q: Quaternion<f64> = (1.0, [2.0, 3.0, 4.0]);
assert!( (30.0_f64.sqrt() - norm(q)).abs() < 1e-12 );
 
// --- Check about overflow --- //
let v: Vector3<f32> = [1e15, 2e20, -3e15];
assert_eq!( dot(v, v).sqrt(), f32::INFINITY );  // Oh...
 
#[cfg(not(feature = "norm-sqrt"))]
assert_eq!( norm(v), 2e20 );  // Excellent!