[Tutor] building nonbinary trees

Vincent Wan wan at walrus.us
Fri Nov 18 02:20:33 CET 2005


I would like to have a tree data structure with trees whose nodes  
could have an arbitrary
number of descendants and that I could iterate over by the names of  
nodes

I'v got a start but I'm stuck because I don't understand how to call  
a tree's nodes by name.

Here is the code I have so far:

import random

# constants that control the simulation
NUMBER_REPS = 10        # run's the simulation
MAX_LINAGES = 10        # number of species in each run
BRANCHING_PROBABILITY = 0.5

class Tree(object):
     numLinages = 0
     class Node(object):
         def __init__(self, name):
             self.name = name
             self.alive = True
             self.descendents = []
             Tree.numLinages += 1
     def __init__(self):
         self.rootnode = Tree.Node(0)
     def AddBranch(self, linage, offspring):
         new = Tree.Node(offspring)
         self.descendents.append(new)
     def NumLinages(  ):
         return Tree.numLinages
     NumLinages = staticmethod(NumLinages)

currentTree = Tree()
print Tree.NumLinages()

for i in range(NUMBER_REPS):
     j = 0
     while j <= currentTree.NumLinages():
         if random.random() >= BRANCHING_PROBABILITY:
             currentTree.AddBranch(j, currentTree.NumLinages() + 1)
         j += 1


thank you,


Vincent Wan

------------------------------------------------------------------------ 
--------------
PhD Candidate
Committee on the Conceptual and Historical Studies of Science
University of Chicago

PO Box 73727
Fairbanks, AK 99707

wan AT walrus DOT us (change CAPS to @ and . )



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