用Python3实现的Mycin专家系统简单实例

 from sys import stderr
 #########################
 TRUE = 1 #定义返回值
 FALSE = 0
 FACT_LENGTH = 9  #'''前提与结论总数'''
 PRMS_LENGTH = 2  #'''每条规则的前提个数'''
 PREMISE = 7 #'''前提数量'''
 RULE_LENGTH = 4  #'''规则数量'''
 LIMIT = 0.5      #'''结论阈值'''
 AND = 1         #'''规则前提逻辑关系'''
 OR = 0
 VH = 0.9       #'''规则前提可信度初始化'''
 H = 0.7
 M = 0.5
 #double Rule_CF[RULE_LENGTH]
 Rule_CF = [0.0]*(RULE_LENGTH+1)
 Str = ["E1", "E2", "E3", "E4", "E5",
 "E6", "E7", "H1", "H", "\0"]
 Fuzz = [None]*10
 Input = [None]*PREMISE
 Repeat = -111   #'''重新输入变量'''

 #'''知识表达'''
 Sign=[0,0,0,0,0,0,0,0,1]
 Rulep=[[1,2,0],[4,5,0],[6,8,0],[3,7,0]]
 Rulec=[[9,'AND'],[8,'AND'],[7,'AND'],[9,'OR']]
 ##
 def Max(a, b): #  '''可信度计算'''
     return a if a>b else b
 def Min(a, b):
     return b if a>b else a
 def Mix(x, y):
     return (x+y-x*y)

 class fact(object):  #'''定义事实类'''
     def __init__(self,Num,NamInput):
         self.Number=Num    #'''事实编号'''
         self.Active=False  #'''记录事实的激活状态'''
         self.CF=0  #'''事实可信度'''
         self.SignNum=0  #'''输出标记'''
         self.Name=NamInput  #'''事实内容'''
     def Fuzz(i):   #'''定义可信度模糊函数'''
         pass
 ###
     def Input(self,int):
         pass
     def GetName(self):
         return self.Name
     def GetNumber(self):
         return self.Number
     def GetAct(self):
         return self.Active
     def PutAct(self,Act):
         self.Active=Act
     def PutFunc(self,f):
         self.Fuzz=f
     def GetCF(self):
         return self.CF
     def PutCF(self,i):
         if isinstance(i,int):
             self.CF=self.Fuzz(i)
             return self.CF
         else:
             self.CF=i
     def PutSign(self,i):
             self.Sign =i
     def GetSign(self):
         return self.Sign

 class rule(object):   #'''定义规则类'''

     def GetConc():
         return self.Conc
     def GetName():
         return self.Name
     def __init__(self,P,C,Rule_CF_Val):
          #'''构造规则函数'''
         #print(P)
         self.List=[None]*2
         self.Name="Rule Name"
         self.List[0]=P[0]
         self.List[1]=P[1]
         self.Logic=C[1]
         self.Conc=C[0]
         self.RCFi=Rule_CF_Val
         self.Next=None    

     def __del__(self):  #'''构造释放规则空间函数'''
         #delete Name
         #delete []List
         pass

     def Query(self):  #  '''构造推理函数'''
         sign=0
         temps=['']*10
         choose=""
         #fact* (*temp)=Fact
         temp=Fact
         while (sign<PRMS_LENGTH):
             #for(;(*temp)!=NULL;temp=temp+1)
             for index in range(len(temp)):
                 if(temp[index].GetNumber()==self.List[sign]): break
             if(temp[index]==None): return FALSE
             if(temp[index].GetAct()>0):
                 sign=sign+1
                 temp=Fact
             else:
                 temp[index].Input(temp[index].GetNumber())
                 choose=input() #scanf("%s",choose)
                 # flushall()
                 print()
                 if choose.lower()=="q":
                     return TRUE
                 if str(int(choose))!= choose :
                     continue
                 if temp[index].PutCF(int(choose))==int(Repeat):
                     continue
                 temp[index].PutAct(TRUE)
         for index in range(len(temp)):
             if(temp[index].GetNumber()==self.Conc): break
         if(temp[index]==None): return FALSE
         temp[index].PutCF(Mix(temp[index].GetCF(),self.CF()))
         temp[index].PutAct(1)
         return FALSE

     def CF(self):  #'''构造可信度推理函数'''
         if self.Logic:
             i=Min(Fact[self.List[0]-1].GetCF(),Fact[self.List[1]-1].GetCF())
             i=i*self.RCFi
             return i

      #################
 ##
 Fact=[fact]*FACT_LENGTH

 #########################
 def Init():  #'''初始化函数'''
     DefFuncArray()
     DefInput()
     DefRule_CF()

 def Input1(i):
      print("按q或Q退出")
      print("请输入事实:E[",i,"的可信度")
      print("可信度为：")
      print(" [1]高")
      print(" [2]中")
      print(" [3]低")

 def Input2(i=3):
      print("按q或Q退出")
      print("请输入事实 E[",i,"]数值[30-45]：")  

 def Input3(i=4):
      print("按q或Q退出")
      print("请输入事实 E[",i,"]数值[60,160]：")

 def Fuzz1(sign):
     switcher = {
         1: VH,
         2: H,
         3: M,
     }
     if(sign in switcher.keys()):
         return switcher[sign]
     else:
         stderr.write("请重新输入！")
         return Repeat    

 def Fuzz2(sign):
     if sign<30 or sign>45:
         stderr.write("请重新输入！")
         return Repeat
     i=(sign-37.0)/9.0
     return i if i>0 else -i

 def Fuzz3(sign):
     if sign<60 or sign>160:
         stderr.write("请重新输入！")
         return Repeat

     i=(sign-60.0)/100.0
     return(i)

 def DefFuncArray():
     for i in range(4):
         Fuzz[i]=Fuzz1
     Fuzz[4]=Fuzz2
     Fuzz[5]=Fuzz3

 def DefInput():
     for i in range(4):
         Input[i]=Input1
     Input[4]=Input2
     Input[5]=Input3

 #'''定义规则的可信度'''
 def DefRule_CF():
     Rule_CF[0]=0.9
     Rule_CF[1]=1.0
     Rule_CF[2]=0.9
     Rule_CF[3]=0.9

 def main():
     #rule *Rule,*R
     #int i=0
     Init()
     #while(*Str[i]) #   '''激活事实对象集'''
     for i in range(len(Fact)):
         Fact[i]=fact((i+1),Str[i])
         #print(Fact[i].GetName())
         Fact[i].PutSign(Sign[i])
     for s in range(PREMISE):
         Fact[s].Input=Input[s]
         Fact[s].PutFunc(Fuzz[s])

     Rule=None
     for i in range(RULE_LENGTH-1,-1,-1): #'''激活规则对象集'''
         if(i<0): return FALSE
         print(i)
         R=rule(Rulep[i],Rulec[i],Rule_CF[i])
         R.Next=Rule
         Rule=R

     R=Rule
     while(True):
            if(R.Query()): break
            R=R.Next
            if(not R): break

     #for(i=0;i<FACT_LENGTH;i++)  '''给出结论'''
     for i in range(FACT_LENGTH):
          if Fact[i].GetCF()>LIMIT and Fact[i].GetSign()==1:
                 Fact[i].PutSign(0)
                 print(" 结论为：")
                 print(Fact[i].GetName())
                 print(" 其可信度为：")
                 print(Fact[i].GetCF())

     print("运行结束。")
     input()
     return TRUE

 if __name__=='__main__':
     main()