################################################################################
#
# This file is part of Gato (Graph Animation Toolbox)
# You can find more information at
# http://gato.sf.net
#
# file: DataStructures.py
# author: Alexander Schliep (schliep@molgen.mpg.de)
#
# Copyright (C) 1998-2005, Alexander Schliep, Winfried Hochstaettler and
# Copyright 1998-2001 ZAIK/ZPR, Universitaet zu Koeln
#
# Contact: schliep@molgen.mpg.de, wh@zpr.uni-koeln.de
#
# Information: http://gato.sf.net
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Library General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public
# License along with this library; if not, write to the Free
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
#
#
# This file is version $Revision: 1.19 $
# from $Date: 2005/02/22 11:12:45 $
# last change by $Author: schliep $.
#
################################################################################
from GatoGlobals import *
################################################################################
#
# Embedding
#
################################################################################
class Point2D:
""" Simple Wrapper class for a point in 2D-space. Used for Graph
Embeddings. Use: Point2D([x,y]) or Point2D(x,y) """
def __init__(self, x = None, y = None):
if y == None:
if x == None:
self.x = 0
self.y = 0
else:
self.x = x[0]
self.y = x[1]
self.x = x
self.y = y
################################################################################
#
# Vertex Labeling
#
################################################################################
class VertexLabeling:
""" Simple Wrapper class for any mapping of vertices to values.
E.g.,
- strings (for labels)
- Point2D (for embeddings) """
def __init__(self):
self.label = {}
def __setitem__(self, v, val):
self.label[v] = val
def __getitem__(self, v):
return self.label[v]
def keys(self):
return self.label.keys()
def QDefined(self,v):
return v in self.label.keys()
class VertexWeight(VertexLabeling):
def __init__(self, theGraph, initialWeight = None):
VertexLabeling.__init__(self)
self.G = theGraph
self.integer = 0
if initialWeight is not None:
self.SetAll(initialWeight)
def QInteger(self):
""" Returns 1 if all weights are integers, 0 else """
return self.integer
def Integerize(self):
if not self.integer:
for v in self.label.keys():
self.label[v] = int(round(self.label[v]))
self.integer = 1
def SetAll(self, initialWeight):
for v in self.G.vertices:
self.label[v] = initialWeight
################################################################################
#
# Edge Labeling
#
################################################################################
class EdgeLabeling:
""" Simple wrapper class for any mapping of edges to values.
E.g.,
- draw edges (for GraphDisplay)
- weights (for embeddings)
Use EdgeLabeling[(u,v)] for access """
def __init__(self):
self.label = {}
def __setitem__(self, e, val): # Use with (tail,head)
self.label[e] = val
def __getitem__(self, e):
return self.label[e]
def QDefined(self,e):
return e in self.label.keys()
class EdgeWeight(EdgeLabeling):
""" Simple class for storing edge weights.
Use EdgeWeight[(u,v)] for access, undirected graphs are
handled properly. """
def __init__(self, theGraph, initialWeight = None):
EdgeLabeling.__init__(self)
self.G = theGraph
self.integer = 0
if initialWeight is not None:
self.SetAll(initialWeight)
def __setitem__(self, e, val): # Use with (tail,head)
if self.G.QDirected():
self.label[e] = val
else:
try:
tmp = self.label[(e[1], e[0])]
self.label[(e[1], e[0])] = val
except KeyError:
self.label[e] = val
def __getitem__(self, e):
if self.G.QDirected():
return self.label[e]
else:
try:
return self.label[(e[1], e[0])]
except KeyError:
return self.label[e]
def QInteger(self):
""" Returns 1 if all weights are integers, 0 else """
return self.integer
def Integerize(self):
if not self.integer:
for e in self.label.keys():
self.label[e] = int(round(self.label[e]))
self.integer = 1
def SetAll(self, initialWeight):
for e in self.G.Edges():
self.label[e] = initialWeight
################################################################################
#
# Queue
#
################################################################################
class Queue:
""" Simple Queue class implemented as a Python list:
XXX check whether replaceble by library queue"""
def __init__(self, elems=None):
if elems == None:
self.contents = []
else:
self.contents = elems[:]
def Append(self,v):
self.contents.append(v)
def Top(self):
v = self.contents[0]
self.contents = self.contents[1:]
return v
def Clear(self):
self.contents = []
def IsEmpty(self):
return (len(self.contents) == 0)
def IsNotEmpty(self):
return (len(self.contents) > 0)
def Contains(self,v):
return v in self.contents
################################################################################
#
# PriorityQueue
#
################################################################################
class PQImplementation(dict):
""" Heap based implementation """
def __init__(self):
'''Initialize priorityDictionary by creating binary heap of
pairs (value,key). Note that changing or removing a dict
entry will not remove the old pair from the heap until it is
found by smallest() or until the heap is rebuilt.'''
self.__heap = []
dict.__init__(self)
def smallest(self):
'''Find smallest item after removing deleted items from heap.'''
if len(self) == 0:
raise IndexError, "smallest of empty priorityDictionary"
heap = self.__heap
while heap[0][1] not in self or self[heap[0][1]] != heap[0][0]:
lastItem = heap.pop()
insertionPoint = 0
while 1:
smallChild = 2*insertionPoint+1
if smallChild+1 < len(heap) and \
heap[smallChild] > heap[smallChild+1]:
smallChild += 1
if smallChild >= len(heap) or lastItem <= heap[smallChild]:
heap[insertionPoint] = lastItem
break
heap[insertionPoint] = heap[smallChild]
insertionPoint = smallChild
return heap[0][1]
def __iter__(self):
'''Create destructive sorted iterator of priorityDictionary.'''
def iterfn():
while len(self) > 0:
x = self.smallest()
yield x
del self[x]
return iterfn()
def deleteMin(self):
x = self.smallest()
del self[x]
return x
def __setitem__(self,key,val):
'''Change value stored in dictionary and add corresponding
pair to heap. Rebuilds the heap if the number of deleted
items grows too large, to avoid memory leakage.'''
dict.__setitem__(self,key,val)
heap = self.__heap
if len(heap) > 2 * len(self):
self.__heap = [(v,k) for k,v in self.iteritems()]
self.__heap.sort() # builtin sort likely faster than O(n) heapify
else:
newPair = (val,key)
insertionPoint = len(heap)
heap.append(None)
while insertionPoint > 0 and \
newPair < heap[(insertionPoint-1)//2]:
heap[insertionPoint] = heap[(insertionPoint-1)//2]
insertionPoint = (insertionPoint-1)//2
heap[insertionPoint] = newPair
def setdefault(self,key,val):
'''Reimplement setdefault to call our customized __setitem__.'''
if key not in self:
self[key] = val
return self[key]
def update(self, other):
for key in other.keys():
self[key] = other[key]
class PriorityQueue:
""" A simple priority queue giving minimal valued items first.
Interface only ... """
def __init__(self):
self.pq = PQImplementation()
def Insert(self,value,sortKey):
self.pq[value] = sortKey
def DeleteMin(self):
""" Return and delete minimal value with minimal sortKey from queue. """
return self.pq.deleteMin()
def DecreaseKey(self,value,newSortKey):
if self.pq.has_key(value):
self.pq[value] = newSortKey
else:
print "PriorityQueue: DecreaseKey of non-existing key"
raise KeyError, "PriorityQueue: DecreaseKey of non-existing key"
def Clear(self):
del self.pq
self.pq = PQImplementation()
def IsEmpty(self):
return (len(self.pq) == 0)
def IsNotEmpty(self):
return (len(self.pq) > 0)
################################################################################
#
# Stack
#
################################################################################
class Stack:
""" Simple Stack class implemented as a Python list """
def __init__(self):
self.contents = []
def Push(self,v):
self.contents.append(v)
def Pop(self):
v = self.contents[-1]
self.contents = self.contents[:-1]
return v
def Clear(self):
self.contents = []
def IsEmpty(self):
return (len(self.contents) == 0)
def IsNotEmpty(self):
return (len(self.contents) > 0)
def Contains(self,v):
return v in self.contents
################################################################################
#
# Set
#
################################################################################
class Set:
def __init__(self):
self.members = []
return
def __getitem__(self,key):
return self.members[key]
def Add(self, e):
self.members.append(e)
return
def Delete(self, e):
try:
self.members.remove(e)
except:
None
return
def IsNotEmpty(self):
return len(self.members) > 0
def Contains(self,e):
return e in self.members
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