problema con clases

[razpeitia]

El problema es que al redefinir __init__, estas redifiniendo el constructor y con ello los miembros en ella.

Lo ideal seria hacer lo siguiente

Código python:

import scipy as sp
import scipy.linalg as linalg
 
class Solution:
    def __init__(self):
        self.feed_flow = 70.0 
        self.feed = sp.array([0.15,0.25,0.4,0.2])
        self.comp_names = ("xylene", "styrene", "toluene", "benzene")
        self.var=("D_1", "B_1", "D_2", "B_2")
        self.xylene = sp.array([0.07,0.18,0.15,0.24])
        self.styrene = sp.array([0.04,0.24,0.1,0.65])
        self.toluene = sp.array([0.54,0.42,0.54,0.1])
        self.benzene = sp.array([0.35,0.16,0.21,0.01])
        T0_comp_frac = self.feed_flow * self.feed    # component fraction on first tower (T0)
        self.comp_eq = sp.array([self.xylene, self.styrene,
                                 self.toluene, self.benzene]) #components linear equations
        self.solve= sp.array(linalg.solve(self.comp_eq, T0_comp_frac))
        self.D = self.solve[0] + self.solve[1]
        self.B = self.solve[2] + self.solve[3]
       
    def comp(self):
        print "D= %s" % self.D
        print "B= %s" % self.B
        for i in range(len(self.var)):
                print self.var[i], "=", self.solve[i]
        flowname= ("D","B")
        x = 0
        while x<= 3:
            y=0
            z=0
            while y<=2:
                temp = (self.comp_eq[x,y]*self.solve[y] +
                        self.comp_eq[x,y+1]*self.solve[y+1])/(self.solve[y]+self.solve[y+1])
                y+=2
                print self.comp_names[x]+ " in "+ flowname[z]+" = ", temp
                z+=1
            x+=1
    
class Solution2(Solution):
    def set_feed_flow(self, percent):
        self.feed_flow = 70.0 - 70.0 * percent
    
       
if __name__=="__main__":
    solution=Solution()
    solution.comp()
    print "*" * 80
    percent = 0.01
    solution2=Solution2()
    solution2.set_feed_flow(0.01)
    solution2.comp()
 

Espero haberte ayudado