326 lines
9.2 KiB
Rust
326 lines
9.2 KiB
Rust
use approx::{AbsDiffEq, RelativeEq, UlpsEq};
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use num_complex::Complex;
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use std::fmt;
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use alga::general::Real;
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use base::{Matrix2, Matrix3, Unit, Vector1};
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use geometry::Rotation2;
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/// A complex number with a norm equal to 1.
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pub type UnitComplex<N> = Unit<Complex<N>>;
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impl<N: Real> UnitComplex<N> {
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/// The rotation angle in `]-pi; pi]` of this unit complex number.
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///
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/// # Example
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/// ```
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/// # use nalgebra::UnitComplex;
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/// let rot = UnitComplex::new(1.78);
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/// assert_eq!(rot.angle(), 1.78);
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/// ```
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#[inline]
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pub fn angle(&self) -> N {
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self.im.atan2(self.re)
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}
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/// The sine of the rotation angle.
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///
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/// # Example
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/// ```
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/// # use nalgebra::UnitComplex;
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/// let angle = 1.78f32;
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/// let rot = UnitComplex::new(angle);
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/// assert_eq!(rot.sin_angle(), angle.sin());
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/// ```
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#[inline]
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pub fn sin_angle(&self) -> N {
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self.im
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}
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/// The cosine of the rotation angle.
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///
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/// # Example
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/// ```
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/// # use nalgebra::UnitComplex;
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/// let angle = 1.78f32;
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/// let rot = UnitComplex::new(angle);
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/// assert_eq!(rot.cos_angle(),angle.cos());
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/// ```
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#[inline]
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pub fn cos_angle(&self) -> N {
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self.re
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}
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/// The rotation angle returned as a 1-dimensional vector.
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///
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/// This is generally used in the context of generic programming. Using
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/// the `.angle()` method instead is more common.
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#[inline]
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pub fn scaled_axis(&self) -> Vector1<N> {
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Vector1::new(self.angle())
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}
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/// The rotation axis and angle in ]0, pi] of this complex number.
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///
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/// This is generally used in the context of generic programming. Using
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/// the `.angle()` method instead is more common.
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/// Returns `None` if the angle is zero.
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#[inline]
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pub fn axis_angle(&self) -> Option<(Unit<Vector1<N>>, N)> {
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let ang = self.angle();
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if ang.is_zero() {
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None
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} else if ang.is_sign_negative() {
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Some((Unit::new_unchecked(Vector1::x()), -ang))
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} else {
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Some((Unit::new_unchecked(-Vector1::<N>::x()), ang))
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}
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}
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/// The underlying complex number.
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///
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/// Same as `self.as_ref()`.
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///
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/// # Example
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/// ```
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/// # extern crate num_complex;
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/// # extern crate nalgebra;
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/// # use num_complex::Complex;
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/// # use nalgebra::UnitComplex;
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/// let angle = 1.78f32;
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/// let rot = UnitComplex::new(angle);
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/// assert_eq!(*rot.complex(), Complex::new(angle.cos(), angle.sin()));
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/// ```
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#[inline]
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pub fn complex(&self) -> &Complex<N> {
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self.as_ref()
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}
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/// Compute the conjugate of this unit complex number.
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///
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/// # Example
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/// ```
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/// # use nalgebra::UnitComplex;
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/// let rot = UnitComplex::new(1.78);
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/// let conj = rot.conjugate();
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/// assert_eq!(rot.complex().im, -conj.complex().im);
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/// assert_eq!(rot.complex().re, conj.complex().re);
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/// ```
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#[inline]
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pub fn conjugate(&self) -> Self {
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UnitComplex::new_unchecked(self.conj())
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}
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/// Inverts this complex number if it is not zero.
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///
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/// # Example
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/// ```
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/// # #[macro_use] extern crate approx;
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/// # extern crate nalgebra;
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/// # use nalgebra::UnitComplex;
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/// let rot = UnitComplex::new(1.2);
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/// let inv = rot.inverse();
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/// assert_relative_eq!(rot * inv, UnitComplex::identity(), epsilon = 1.0e-6);
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/// assert_relative_eq!(inv * rot, UnitComplex::identity(), epsilon = 1.0e-6);
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/// ```
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#[inline]
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pub fn inverse(&self) -> Self {
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self.conjugate()
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}
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/// The rotation angle needed to make `self` and `other` coincide.
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///
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/// # Example
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/// ```
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/// # #[macro_use] extern crate approx;
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/// # extern crate nalgebra;
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/// # use nalgebra::UnitComplex;
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/// let rot1 = UnitComplex::new(0.1);
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/// let rot2 = UnitComplex::new(1.7);
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/// assert_relative_eq!(rot1.angle_to(&rot2), 1.6);
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/// ```
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#[inline]
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pub fn angle_to(&self, other: &Self) -> N {
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let delta = self.rotation_to(other);
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delta.angle()
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}
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/// The unit complex number needed to make `self` and `other` coincide.
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///
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/// The result is such that: `self.rotation_to(other) * self == other`.
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///
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/// # Example
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/// ```
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/// # #[macro_use] extern crate approx;
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/// # extern crate nalgebra;
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/// # use nalgebra::UnitComplex;
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/// let rot1 = UnitComplex::new(0.1);
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/// let rot2 = UnitComplex::new(1.7);
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/// let rot_to = rot1.rotation_to(&rot2);
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///
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/// assert_relative_eq!(rot_to * rot1, rot2);
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/// assert_relative_eq!(rot_to.inverse() * rot2, rot1);
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/// ```
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#[inline]
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pub fn rotation_to(&self, other: &Self) -> Self {
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other / self
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}
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/// Compute in-place the conjugate of this unit complex number.
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///
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/// # Example
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/// ```
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/// # #[macro_use] extern crate approx;
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/// # extern crate nalgebra;
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/// # use nalgebra::UnitComplex;
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/// let angle = 1.7;
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/// let rot = UnitComplex::new(angle);
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/// let mut conj = UnitComplex::new(angle);
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/// conj.conjugate_mut();
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/// assert_eq!(rot.complex().im, -conj.complex().im);
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/// assert_eq!(rot.complex().re, conj.complex().re);
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/// ```
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#[inline]
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pub fn conjugate_mut(&mut self) {
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let me = self.as_mut_unchecked();
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me.im = -me.im;
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}
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/// Inverts in-place this unit complex number.
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///
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/// # Example
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/// ```
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/// # #[macro_use] extern crate approx;
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/// # extern crate nalgebra;
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/// # use nalgebra::UnitComplex;
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/// let angle = 1.7;
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/// let mut rot = UnitComplex::new(angle);
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/// rot.inverse_mut();
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/// assert_relative_eq!(rot * UnitComplex::new(angle), UnitComplex::identity());
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/// assert_relative_eq!(UnitComplex::new(angle) * rot, UnitComplex::identity());
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/// ```
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#[inline]
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pub fn inverse_mut(&mut self) {
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self.conjugate_mut()
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}
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/// Raise this unit complex number to a given floating power.
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///
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/// This returns the unit complex number that identifies a rotation angle equal to
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/// `self.angle() × n`.
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///
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/// # Example
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/// ```
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/// # use nalgebra::UnitComplex;
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/// let rot = UnitComplex::new(0.78);
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/// let pow = rot.powf(2.0);
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/// assert_eq!(pow.angle(), 2.0 * 0.78);
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/// ```
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#[inline]
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pub fn powf(&self, n: N) -> Self {
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Self::from_angle(self.angle() * n)
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}
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/// Builds the rotation matrix corresponding to this unit complex number.
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///
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/// # Example
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/// ```
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/// # use nalgebra::{UnitComplex, Rotation2};
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/// # use std::f32;
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/// let rot = UnitComplex::new(f32::consts::FRAC_PI_6);
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/// let expected = Rotation2::new(f32::consts::FRAC_PI_6);
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/// assert_eq!(rot.to_rotation_matrix(), expected);
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/// ```
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#[inline]
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pub fn to_rotation_matrix(&self) -> Rotation2<N> {
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let r = self.re;
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let i = self.im;
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Rotation2::from_matrix_unchecked(Matrix2::new(r, -i, i, r))
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}
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/// Converts this unit complex number into its equivalent homogeneous transformation matrix.
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///
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/// # Example
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/// ```
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/// # use nalgebra::{UnitComplex, Matrix3};
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/// # use std::f32;
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/// let rot = UnitComplex::new(f32::consts::FRAC_PI_6);
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/// let expected = Matrix3::new(0.8660254, -0.5, 0.0,
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/// 0.5, 0.8660254, 0.0,
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/// 0.0, 0.0, 1.0);
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/// assert_eq!(rot.to_homogeneous(), expected);
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/// ```
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#[inline]
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pub fn to_homogeneous(&self) -> Matrix3<N> {
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self.to_rotation_matrix().to_homogeneous()
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}
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}
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impl<N: Real + fmt::Display> fmt::Display for UnitComplex<N> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "UnitComplex angle: {}", self.angle())
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}
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}
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impl<N: Real> AbsDiffEq for UnitComplex<N> {
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type Epsilon = N;
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#[inline]
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fn default_epsilon() -> Self::Epsilon {
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N::default_epsilon()
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}
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#[inline]
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fn abs_diff_eq(&self, other: &Self, epsilon: Self::Epsilon) -> bool {
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self.re.abs_diff_eq(&other.re, epsilon) && self.im.abs_diff_eq(&other.im, epsilon)
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}
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}
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impl<N: Real> RelativeEq for UnitComplex<N> {
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#[inline]
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fn default_max_relative() -> Self::Epsilon {
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N::default_max_relative()
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}
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#[inline]
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fn relative_eq(
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&self,
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other: &Self,
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epsilon: Self::Epsilon,
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max_relative: Self::Epsilon,
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) -> bool
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{
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self.re.relative_eq(&other.re, epsilon, max_relative)
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&& self.im.relative_eq(&other.im, epsilon, max_relative)
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}
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}
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impl<N: Real> UlpsEq for UnitComplex<N> {
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#[inline]
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fn default_max_ulps() -> u32 {
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N::default_max_ulps()
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}
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#[inline]
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fn ulps_eq(&self, other: &Self, epsilon: Self::Epsilon, max_ulps: u32) -> bool {
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self.re.ulps_eq(&other.re, epsilon, max_ulps)
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&& self.im.ulps_eq(&other.im, epsilon, max_ulps)
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}
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}
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impl<N: Real> From<UnitComplex<N>> for Matrix3<N> {
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#[inline]
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fn from(q: UnitComplex<N>) -> Matrix3<N> {
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q.to_homogeneous()
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}
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}
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impl<N: Real> From<UnitComplex<N>> for Matrix2<N> {
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#[inline]
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fn from(q: UnitComplex<N>) -> Matrix2<N> {
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q.to_rotation_matrix().unwrap()
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}
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}
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