Add `.*_scalar()` to `Matrix1`
Allows for converting a `Matrix1` to a scalar without having to index.
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@ -2244,3 +2244,102 @@ where
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Unit::new_unchecked(crate::convert_ref(self.as_ref()))
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}
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}
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impl<T, S> Matrix<T, U1, U1, S>
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where
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S: RawStorage<T, U1, U1>,
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{
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/// Returns a reference to the single element in this matrix.
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///
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/// As opposed to indexing, using this provides type-safety
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/// when flattening dimensions.
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///
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/// # Example
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/// ```
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/// # use nalgebra::Vector3;
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/// let v = Vector3::new(0., 0., 1.);
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/// let inner_product: f32 = *(v.transpose() * v).as_scalar();
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/// ```
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///
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///```compile_fail
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/// # use nalgebra::Vector3;
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/// let v = Vector3::new(0., 0., 1.);
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/// let inner_product = (v * v.transpose()).item(); // Typo, does not compile.
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///```
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pub fn as_scalar(&self) -> &T {
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&self[(0, 0)]
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}
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/// Get a mutable reference to the single element in this matrix
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///
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/// As opposed to indexing, using this provides type-safety
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/// when flattening dimensions.
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///
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/// # Example
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/// ```
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/// # use nalgebra::Vector3;
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/// let v = Vector3::new(0., 0., 1.);
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/// let mut inner_product = (v.transpose() * v);
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/// *inner_product.as_scalar_mut() = 3.;
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/// ```
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///
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///```compile_fail
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/// # use nalgebra::Vector3;
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/// let v = Vector3::new(0., 0., 1.);
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/// let mut inner_product = (v * v.transpose());
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/// *inner_product.as_scalar_mut() = 3.;
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///```
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pub fn as_scalar_mut(&mut self) -> &mut T
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where
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S: RawStorageMut<T, U1>,
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{
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&mut self[(0, 0)]
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}
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/// Convert this 1x1 matrix by reference into a scalar.
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///
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/// As opposed to indexing, using this provides type-safety
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/// when flattening dimensions.
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///
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/// # Example
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/// ```
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/// # use nalgebra::Vector3;
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/// let v = Vector3::new(0., 0., 1.);
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/// let mut inner_product: f32 = (v.transpose() * v).to_scalar();
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/// ```
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///
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///```compile_fail
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/// # use nalgebra::Vector3;
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/// let v = Vector3::new(0., 0., 1.);
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/// let mut inner_product: f32 = (v * v.transpose()).to_scalar();
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///```
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pub fn to_scalar(&self) -> T
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where
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T: Clone,
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{
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self.as_scalar().clone()
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}
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}
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impl<T> super::alias::Matrix1<T> {
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/// Convert this 1x1 matrix into a scalar.
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///
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/// As opposed to indexing, using this provides type-safety
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/// when flattening dimensions.
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///
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/// # Example
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/// ```
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/// # use nalgebra::{Vector3, Matrix2, U1};
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/// let v = Vector3::new(0., 0., 1.);
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/// let inner_product: f32 = (v.transpose() * v).into_scalar();
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/// assert_eq!(inner_product, 1.);
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/// ```
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///
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///```compile_fail
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/// # use nalgebra::Vector3;
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/// let v = Vector3::new(0., 0., 1.);
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/// let mut inner_product: f32 = (v * v.transpose()).into_scalar();
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///```
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pub fn into_scalar(self) -> T {
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let [[scalar]] = self.data.0;
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scalar
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}
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}
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