README.md

Sparse Matrix library

Sparse Matrix library implements sparse matrix using CSR format. Using this library should be as intuitive as possible (see examples below).

Usage

Loading

To load the library just include the header file.

#include "SparseMatrix/SparseMatrix.h"

Matrix creation

The constructor takes one or two arguments depending on if we want to create a square or non-square matrix. By default, values of all matrix elements are 0.

SparseMatrix<int> a(3); // 3×3 matrix
SparseMatrix<int> b(3, 5); // 3×5 matrix (3 rows, 5 columns)

Matrix operations

Setting element

For inserting new element there is a method set(), which takes 3 arguments - what (value) and where (row, column) we want to insert.

SparseMatrix<int> a(3);
a.set(-5, 2, 3); // inserts value -5 on 2nd row into 3rd column

Getting element

To get the value of specific element use method get():

SparseMatrix<int> a(3);
a.get(2, 3); // returns value of the element on 2nd row in 3rd column (returns 0 if no value has been assigned yet)

Vector multiplication

We can multiply the matrix by vector (but only if the vector has a proper dimension).

SparseMatrix<int> a(3);
vector<int> x(3, 2);
vector<int> result = a.multiply(x);

Matrix multiplication

We can also multiply the matrix by another matrix (again - only if the matrix has proper dimensions).

SparseMatrix<int> a(3, 4);
SparseMatrix<int> b(4, 5);
SparseMatrix<int> result = a.multiply(b);

Matrix addition

When two matrices have the same dimensions, we can add them together.

SparseMatrix<int> a(3, 4);
SparseMatrix<int> b(3, 4);
SparseMatrix<int> result = a.add(b);

Matrix printing

When we want to print the matrix in human readable form, we can simply send it to the output stream.

SparseMatrix<int> a(3);
std::cout << a << endl;