Function kronsum 

pub fn kronsum<'a, T>(
    a: &'a dyn SparseArray<T>,
    b: &'a dyn SparseArray<T>,
    format: &str,
) -> SparseResult<Box<dyn SparseArray<T>>>
where
    T: 'a + Float + Add<Output = T> + AddAssign + Sub<Output = T> + Mul<Output = T> + Div<Output = T> + Debug + Copy + 'static,

Kronecker sum of square sparse arrays

Computes the Kronecker sum of two square sparse arrays. The Kronecker sum of two matrices A and B is the sum of the two Kronecker products: kron(I_n, A) + kron(B, I_m) where A has shape (m,m), B has shape (n,n), and I_m and I_n are identity matrices of shape (m,m) and (n,n), respectively.

The resulting array has shape (mn, mn).

Arguments

• a - First square sparse array
• b - Second square sparse array
• format - Format of the output array (“csr” or “coo”)

Returns

A sparse array representing the Kronecker sum of A and B

Examples

use scirs2_sparse::construct::eye_array;
use scirs2_sparse::combine::kronsum;

let a = eye_array::<f64>(2, "csr").unwrap();
let b = eye_array::<f64>(2, "csr").unwrap();
let c = kronsum(&*a, &*b, "csr").unwrap();

// Verify the shape of Kronecker sum
assert_eq!(c.shape(), (4, 4));

// Verify there is a non-zero element by checking the number of non-zeros
let (rows, cols, data) = c.find();
assert!(rows.len() > 0);
assert!(cols.len() > 0);
assert!(data.len() > 0);