Add `.*_scalar()` to `Matrix1`

Allows for converting a `Matrix1` to a scalar without having to index.
This commit is contained in:
julianknodt 2023-04-12 22:48:31 -07:00
parent f5af5dbff2
commit d9af8650bb
1 changed files with 99 additions and 0 deletions

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@ -2244,3 +2244,102 @@ where
Unit::new_unchecked(crate::convert_ref(self.as_ref()))
}
}
impl<T, S> Matrix<T, U1, U1, S>
where
S: RawStorage<T, U1, U1>,
{
/// Returns a reference to the single element in this matrix.
///
/// As opposed to indexing, using this provides type-safety
/// when flattening dimensions.
///
/// # Example
/// ```
/// # use nalgebra::Vector3;
/// let v = Vector3::new(0., 0., 1.);
/// let inner_product: f32 = *(v.transpose() * v).as_scalar();
/// ```
///
///```compile_fail
/// # use nalgebra::Vector3;
/// let v = Vector3::new(0., 0., 1.);
/// let inner_product = (v * v.transpose()).item(); // Typo, does not compile.
///```
pub fn as_scalar(&self) -> &T {
&self[(0, 0)]
}
/// Get a mutable reference to the single element in this matrix
///
/// As opposed to indexing, using this provides type-safety
/// when flattening dimensions.
///
/// # Example
/// ```
/// # use nalgebra::Vector3;
/// let v = Vector3::new(0., 0., 1.);
/// let mut inner_product = (v.transpose() * v);
/// *inner_product.as_scalar_mut() = 3.;
/// ```
///
///```compile_fail
/// # use nalgebra::Vector3;
/// let v = Vector3::new(0., 0., 1.);
/// let mut inner_product = (v * v.transpose());
/// *inner_product.as_scalar_mut() = 3.;
///```
pub fn as_scalar_mut(&mut self) -> &mut T
where
S: RawStorageMut<T, U1>,
{
&mut self[(0, 0)]
}
/// Convert this 1x1 matrix by reference into a scalar.
///
/// As opposed to indexing, using this provides type-safety
/// when flattening dimensions.
///
/// # Example
/// ```
/// # use nalgebra::Vector3;
/// let v = Vector3::new(0., 0., 1.);
/// let mut inner_product: f32 = (v.transpose() * v).to_scalar();
/// ```
///
///```compile_fail
/// # use nalgebra::Vector3;
/// let v = Vector3::new(0., 0., 1.);
/// let mut inner_product: f32 = (v * v.transpose()).to_scalar();
///```
pub fn to_scalar(&self) -> T
where
T: Clone,
{
self.as_scalar().clone()
}
}
impl<T> super::alias::Matrix1<T> {
/// Convert this 1x1 matrix into a scalar.
///
/// As opposed to indexing, using this provides type-safety
/// when flattening dimensions.
///
/// # Example
/// ```
/// # use nalgebra::{Vector3, Matrix2, U1};
/// let v = Vector3::new(0., 0., 1.);
/// let inner_product: f32 = (v.transpose() * v).into_scalar();
/// assert_eq!(inner_product, 1.);
/// ```
///
///```compile_fail
/// # use nalgebra::Vector3;
/// let v = Vector3::new(0., 0., 1.);
/// let mut inner_product: f32 = (v * v.transpose()).into_scalar();
///```
pub fn into_scalar(self) -> T {
let [[scalar]] = self.data.0;
scalar
}
}