Well, we've reviewed the concept of rules, And it has been understood that, A rule consists roughly of two logical units, Match conditions and actions, It is useless to say so much, Let's define a rule by hand. Here, we still take the INPUT chain in the filter table as an example, because the filter table is responsible for the "filtering" function, and if all messages sent to the local machine need to be filtered, they will first pass through the INPUT chain (PREROUTING chain has no filtering function), which is very similar to the "entry" scenario we refer to. Therefore, using the INPUT chain in the filter table as an example is helpful for us to understand.影片是由李昂执导，高宝成、刘继忠、祝新运主演Not only did I hear the voice, Almost half of the entire position 149 heard it, Then the position was bombed, The soldiers all took up their weapons and held the horses and bees in the air desperately to "hug the fire" (note: meaning to pull the trigger and fire), Even if there are some comrades who did not hear the cry of "fight", When they saw others firing, they followed suit. Those big wasps are abundant, Flying densely and bulky, So when we started shooting, The shooting rate is quite high, After the sound of the gun became one, it gradually became equal to the "buzzing" sound. No one can beat anyone, It feels strange that the two sounds are mixed together. Now that I think about it, It's like a rock band playing "heavy metal" (here "heavy metal" is a genre of rock music, Before the 1970s, This rock style is called 'hard rock', It was later renamed 'heavy metal', Of course, this is one of the more well-recognized explanations about the origin of the "heavy metal" genre of rock music. There are several other different explanations, As it is not relevant to this article, It will not be discussed in detail here), Then they gathered fire and shot for more than ten seconds. The left and right sides of the position were covered with the smashed bodies of this big wasp like rain. But then the bullets hit them more and more scattered in the air, finally forming a "circle", covering the whole position under, and then one by one dive to the ground, although they scattered, but in this way their distribution area is wider, and the spacing is widened, not as dense as before, plus flying fast,张杨沉声道：不错。王穷便微笑告退，往乾元殿去了。Wang Zeduan previously described that the blood-like liquid flowing out of this strange dog after being hit by steel balls produced by anti-infantry mine explosions is also green, Combined with what Zhao Mingkai said now, It can be determined that for this strange dog, Just as blood represents the primary color of human body fluids in red, The primary color of their body fluids is green, And more unified than human beings, After all, the human brain solution is milky white, Unlike blood, However, whether they are blood or brain solution (in fact, I don't know if it is their blood or brain solution, so I used the word "image" to describe them in front. After all, whether they are natural or artificial, they belong to unknown species, but for convenience of description, they are all green.For codes of the same length, theoretically, the further the coding distance between any two categories, the stronger the error correction capability. Therefore, when the code length is small, the theoretical optimal code can be calculated according to this principle. However, it is difficult to effectively determine the optimal code when the code length is slightly larger. In fact, this is an NP-hard problem. However, we usually do not need to obtain theoretical optimal codes, because non-optimal codes can often produce good enough classifiers in practice. On the other hand, it is not that the better the theoretical properties of coding, the better the classification performance, because the machine learning problem involves many factors, such as dismantling multiple classes into two "class subsets", and the difficulty of distinguishing the two class subsets formed by different dismantling methods is often different, that is, the difficulty of the two classification problems caused by them is different. Therefore, one theory has a good quality of error correction, but it leads to a difficult coding for the two-classification problem, which is worse than the other theory, but it leads to a simpler coding for the two-classification problem, and it is hard to say which is better or weaker in the final performance of the model.
