Math4j is a simple java lib for matrix calculation that does not use third-party libs.

Examples

Matrix create

Default create

        Matrix m1 = Matrix.create(4, 4);
        System.out.println(m1);
        System.out.println(m1.get(0,1));

        Matrix m2 = Matrix.zeros(4,4);
        m2.set(3.0, 1, 1);
        System.out.println(m2);

        Matrix m3 = Matrix.random(3, 4);
        System.out.println(m3);

        Matrix m4 = Matrix.random(4, 4);
        System.out.println(m4);

Create Dense Matrix

        Matrix dense1 = new DefaultDenseDoubleMatrix2D(3000, 4000);
        dense1.set(200, 125, 223);
        dense1.get(125, 223);

Create Sparse Matrix

        Matrix sparse1 = new DefaultSparseDoubleMatrix2D(3000, 4000);
        sparse1.set(200, 223, 222);
        sparse1.get(223, 222);

Create High Dimension Matrix

        Matrix highMatrix = Matrix.create(20, 30, 40, 50);
        highMatrix.set(200, 10, 20, 30, 40);
        highMatrix.get(10, 20, 30, 40);

Matrix calculation

        System.out.println(m1.add(m2));
        System.out.println(m1.subtract(m2));
        System.out.println(m3.multiply(m4));

Matrix block

        System.out.println(m1.getMatrix(2, 2));
        System.out.println(m1.getMatrix(Matrix.DIMENSION_WILDCARD, 2)); // get the third cols
        System.out.println(m1.getMatrix(2, Matrix.DIMENSION_WILDCARD)); // get the third rows

Have fun~