正交匹配追踪（OMP）算法属于贪婪算法。而贪婪算法是一种不追求最优解，只希望得到较为满意解的方法。贪婪法一般可以快速得到满意的解，因为它省去了为找最优解要穷尽所有可能而必须耗费的大量时间。贪婪算法常以当前情况为基础作最优选择，而不考虑各种可能的整体情况，所以贪婪算法不要回溯。(Orthogonal matching pursuit (OMP) algorithm belongs to greedy algorithm. Greedy algorithm is a method that does not pursue the optimal solution but only needs satisfactory solutions. Greedy law can generally get a satisfactory solution quickly, because it eliminates the need to exhaust all possible and expensive time for finding the optimal solution. Greedy algorithms are often based on the current situation for optimal selection without considering all possible overall situations, so greedy algorithms do not backtrack.)