# Sparse Bin Mat
A sparse implementation of a binary matrix optimized for row operations.
All elements in a binary matrix are element of the binary field GF2.
That is, they are either 0 or 1 and addition is modulo 2.
## Quick start
To instanciate a matrix, you need to specify the number of columns as well
as the position of 1 in each rows.
```rust
use sparse_bin_mat::SparseBinMat;
// This is the matrix
// 1 0 1 0 1
// 0 1 0 1 0
// 0 0 1 0 0
let matrix = SparseBinMat::new(5, vec![vec![0, 2, 4], vec![1, 3], vec![2]]);
```
It is easy to access elements or rows of a matrix. However,
since the matrix are optimized for row operations, you need
to transpose the matrix if you want to perform column operations.
```rust
let matrix = SparseBinMat::new(5, vec![vec![0, 2, 4], vec![1, 3], vec![2]]);
assert_eq!(matrix.row(1), Some([1, 3].as_ref()));
assert_eq!(matrix.get(0, 0), Some(1));
assert_eq!(matrix.get(0, 1), Some(0));
// The element (0, 7) is out of bound for a 3 x 5 matrix.
assert_eq!(matrix.get(0, 7), None);
```
Adition and multiplication are implemented between matrix references.
```rust
let matrix = SparseBinMat::new(3, vec![vec![0, 1], vec![1, 2], vec![0, 2]]);
let identity = SparseBinMat::identity(3);
let sum = SparseBinMat::new(3, vec![vec![1], vec![2], vec![0]]);
assert_eq!(&matrix + &identity, sum);
assert_eq!(&matrix * &identity, matrix);
```
Many useful operations and decompositions are implemented.
These include, but are not limited to
- rank,
- echelon from,
- normal form,
- tranposition,
- horizontal and vertical concatenations,
- and more ...
Operations are implemented as I need them,
feel welcome to raise an issue if you need a new functionnality.