use super::SparseMatrix;
use crate::{matrix::ge::Matrix, number::Number};
use std::ops::Mul;
fn mul<T>(slf: &Matrix<T>, rhs: &SparseMatrix<T>) -> Matrix<T>
where
T: Number,
{
if slf.cols() != rhs.rows {
panic!("Dimension mismatch.");
}
let s_rows = slf.cols();
let new_matrix_vec = (0..s_rows)
.map(|row| {
(0..rhs.cols)
.map(|col| {
let elems_orig = rhs
.elems
.iter()
.filter(|(&(_r_row, r_col), &_l)| r_col == col)
.map(|(&(r_row, _r_col), &l)| {
let elem = l * slf[(row, r_row)];
elem
})
.sum::<T>();
elems_orig
})
.collect::<Vec<T>>()
})
.collect::<Vec<Vec<T>>>()
.concat();
let new_matrix = Matrix::from(s_rows, new_matrix_vec).unwrap();
new_matrix
}
impl<T> Mul<SparseMatrix<T>> for Matrix<T>
where
T: Number,
{
type Output = Matrix<T>;
fn mul(self, rhs: SparseMatrix<T>) -> Self::Output {
mul(&self, &rhs)
}
}
impl<T> Mul<&SparseMatrix<T>> for Matrix<T>
where
T: Number,
{
type Output = Matrix<T>;
fn mul(self, rhs: &SparseMatrix<T>) -> Self::Output {
mul(&self, rhs)
}
}
impl<T> Mul<SparseMatrix<T>> for &Matrix<T>
where
T: Number,
{
type Output = Matrix<T>;
fn mul(self, rhs: SparseMatrix<T>) -> Self::Output {
mul(self, &rhs)
}
}
impl<T> Mul<&SparseMatrix<T>> for &Matrix<T>
where
T: Number,
{
type Output = Matrix<T>;
fn mul(self, rhs: &SparseMatrix<T>) -> Self::Output {
mul(self, rhs)
}
}
#[cfg(test)]
mod tests {
use crate::*;
#[test]
fn it_works() {
let a = mat![
1.0, 2.0;
3.0, 4.0
];
let b = SparseMatrix::from(
2,
2,
vec![
((0usize, 0usize), 1.0),
((0usize, 1usize), 2.0),
((1usize, 1usize), 2.0),
]
.into_iter()
.collect(),
);
let ab = a * b;
println!("{:?}", ab)
}
}