use crate::algebra::abstr::{Field, Scalar};
use crate::algebra::linear::matrix::Determinant;
use crate::algebra::linear::matrix::UpperTriangular;
impl<T> Determinant<T> for UpperTriangular<T>
where
T: Field + Scalar,
{
/// Calculates the determinant
///
/// # Example
///
/// ```
/// use mathru::algebra::linear::matrix::{Determinant, UpperTriangular, General};
/// use mathru::matrix;
///
/// let a: UpperTriangular<f64> = matrix![ 2.0, 0.0;
/// 5.0, -3.0].into();
/// let det: f64 = a.det();
/// assert_eq!(det, -6.0)
/// ```
fn det(&self) -> T {
let (m, n) = self.matrix.dim();
debug_assert_eq!(m, n);
let mut det = T::one();
for i in 0..m {
det *= self[[i, i]];
}
det
}
}