static double[][] subtract(double[][] matrix1, double[][] matrix2){
		double[][] diff = new double[matrix1.length][matrix1[0].length];
		for(int i = 0; i < diff.length; i++)
			for(int j = 0; j < diff[0].length; j++)
				diff[i][j] = matrix1[i][j] - matrix2[i][j];
		
		return diff;
	}