float[][] multiply(float[][] m1, float[][] m2){
        int r1 = m1.length, c1 = m1[0].length;
        int r2 = m2.length, c2 = m2[0].length;
        float[][] product = new float[m1.length][m2[0].length];
        for(int i = 0; i < r1; i++) {
            for (int j = 0; j < c2; j++) {
                for (int k = 0; k < c1; k++) {
                    product[i][j] += m1[i][k] * m2[k][j];
                }
            }
        }
        return product;
    }