SIR模型是传染病模型中最经典的模型，其中S表示易感者，I表示感染者，R表示恢复者。SIR模型中，染病人群为传染的源头,他通过一定的几率把传染病传给易感人群,他自己也有一定的几率/可以被治愈并免疫,或者死亡;易感人群一旦被感染,就又成为了新的传染源。将人群划分为三类，易感染者、已感染者和已恢复者(recovered )。(The SIR model is the most classical model in the epidemic model, where S represents the susceptible person, I means the infected person, and R represents the restorer. In the SIR model, the infected population is the source of infection, and he passes the infectious disease to the susceptible people through a certain chance. He has a certain chance of being cured, immune, or dead. Once the susceptible population is infected, it becomes a new source of infection. The population was divided into three groups, susceptible persons, infected persons and recovered persons (recovered).)