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SamplingAlgorithms.py
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321 lines (291 loc) · 10.4 KB
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__author__ = 'Chulaka'
import random
import time
import networkx as nx
import numpy
import math
import array
import csv
def randomWalk(G_, keptNodes):
picked = []
random.seed(time.clock())
random.shuffle(G_.nodes())
seed = random.choice(G_.nodes())
current = seed
picked.append(seed)
c = 0.85
temp = 0
num = 1
#print "Added "+str(seed)+ " num is "+str(num)
temp_list = []
num_true = int(100*c)
num_false = 100-num_true
for t_val in range (num_true):
temp_list.append(1)
for f_val in range (num_false):
temp_list.append(0)
while num < keptNodes:
random.shuffle(temp_list)
info_accepted = random.choice(temp_list)
if (info_accepted==1):
neighborlist = G_.neighbors(current)
#prevCurr = current
oneSelected = False
for ind in range(0, len(neighborlist)):
random.seed(time.clock())
random.shuffle(neighborlist)
walkingTo = random.choice(neighborlist)
if (walkingTo not in picked):
num = num+1
temp = num-1
#print "Added "+str(walkingTo)+ " num is "+str(num)
picked.append(walkingTo)
current = walkingTo
oneSelected = True
break
if not oneSelected:
val = temp-1
temp -= 1
current = picked[val]
continue
#temp = temp-1
else:
val = temp-1
temp -= 1
current = picked[val]
continue
print "Size of picked "+str(len(picked))
return picked
def randomSampling(G_, keptNodes):
random.seed(time.clock())
picked = random.sample(set(G_.nodes()), keptNodes)
return picked
def randomDegreeSampling(G_, keptNodes):
probs = []
picked = []
edgecount = float(len(G_.edges()))
for node in G_.nodes():
probs.append(G_.degree(node)/(2*edgecount))
cumSumProbs = cumulative_sum(probs)
cumSumProbs[len(cumSumProbs)-1] = 1.0
num = 0
while num < keptNodes:
random.seed(time.clock())
number = random.random()
for node in range(0, len(G_.nodes())):
if (number <= cumSumProbs[node]):
if(G_.nodes()[node] not in picked):
print "Adding node "+ str(G_.nodes()[node])
picked.append(G_.nodes()[node])
num = num+1
break
else:
#print "Collision"
break
return picked
def randomEigenvectorSampling(G_, keptNodes):
sumEigen = 0.0
eigenvector = nx.eigenvector_centrality_numpy(G_)
for node in G_.nodes():
sumEigen = sumEigen+eigenvector[node]
probs = []
picked = []
for node in G_.nodes():
probs.append(eigenvector[node]/sumEigen)
cumEigenProbs = cumulative_sum(probs)
cumEigenProbs[len(cumEigenProbs)-1] = 1.0
num = 0
while num < keptNodes:
random.seed(time.clock())
number = random.random()
for node in range(0, len(G_.nodes())):
if (number <= cumEigenProbs[node]):
if(G_.nodes()[node] not in picked):
print "Adding node "+ str(G_.nodes()[node])
picked.append(G_.nodes()[node])
num = num+1
break
else:
#print "Collision"
break
return picked
def core_number_reachability(G_, keptNodes):
if G_.is_multigraph():
raise nx.NetworkXError(
'MultiGraph and MultiDiGraph types not supported.')
if G_.number_of_selfloops()>0:
raise nx.NetworkXError(
'Input graph has self loops; the core number is not defined.',
'Consider using G.remove_edges_from(G.selfloop_edges()).')
if G_.is_directed():
import itertools
def neighbors(v):
return itertools.chain.from_iterable([G_.predecessors_iter(v),
G_.successors_iter(v)])
else:
neighbors=G_.neighbors_iter
degrees=G_.degree()
# sort nodes by degree
nodes=sorted(degrees,key=degrees.get)
# where degrees change
bin_boundaries=[0]
curr_degree=0
for i,v in enumerate(nodes):
if degrees[v]>curr_degree:
bin_boundaries.extend([i]*(degrees[v]-curr_degree))
curr_degree=degrees[v]
#degree dictrionary
node_pos = dict((v,pos) for pos,v in enumerate(nodes))
# initial guesses for core is degree
core=degrees
nbrs=dict((v,set(neighbors(v))) for v in G_)
for v in nodes:
for u in nbrs[v]:
if core[u] > core[v]:
nbrs[u].remove(v)
pos=node_pos[u]
bin_start=bin_boundaries[core[u]]
node_pos[u]=bin_start
node_pos[nodes[bin_start]]=pos
nodes[bin_start],nodes[pos]=nodes[pos],nodes[bin_start]
bin_boundaries[core[u]]+=1
core[u]-=1
#coreSorted = sorted(core.items(), key=lambda x: x[1], reverse=True)
coreSorted=sorted(core,key=core.get, reverse=True)
return coreSorted[:keptNodes]
#return core
def cumulative_sum(L):
CL = []
csum = 0
for x in L:
csum += x
CL.append(csum)
return CL
def topDegreeSubset(fileName, keptNodes ):
sortedDegreeList = []
sortedEigenvectorList = []
sortedClosenessList = []
sortedBetweennessList = []
#fileName = "All_lesmis.csv.csv"
val = 0
with open(fileName, 'rU') as csvfile:
filereader = csv.reader(csvfile)
for row in filereader:
val = val+1
#print "Reading row "+str(val)
if row is not None and len(row) > 0:
sortedDegreeList.append(int(row[0]))
sortedEigenvectorList.append(int(row[1]))
sortedClosenessList.append(int(row[2]))
sortedBetweennessList.append(int(row[3]))
csvfile.close()
#topPer = int(round(numNodes*precentToKeep))
degreeTopPer = sortedDegreeList[:keptNodes]
return degreeTopPer
def SimilaritySample(G_, keptNodes):
lowerbound = 0.95*keptNodes
upperbound = 1.05*keptNodes
print "Range "+str(lowerbound)+"-"+str(upperbound)
similarityMeasure = 0.81
nodeSet = G_.nodes()
while True:
random.seed(time.clock())
random.shuffle(nodeSet)
sample = set([])
sample.add(nodeSet[0])
#Add first node to sample
for node in nodeSet:
# For each node v in the network
matched = False
for sampledNode in sample:
nodeNeighbors = G_.neighbors(node)
#nodeNeighbors.append(node)
sampleNeighbors = G_.neighbors(sampledNode)
#sampleNeighbors.append(sampledNode)
# If v does not have more than simMeasure similarity with any node in the sample
# Add v to Sample
intersection = list(set(nodeNeighbors).intersection(set(sampleNeighbors)))
intersectionPer = 0.0
if len(nodeNeighbors) < len(sampleNeighbors):
intersectionPer = len(intersection)/float(len(nodeNeighbors))
else:
intersectionPer = len(intersection)/float(len(sampleNeighbors))
#print len(nodeNeighbors)
#print len(sampleNeighbors)
#print intersectionPer
if (intersectionPer > similarityMeasure):
if (len(nodeNeighbors) <= len(sampleNeighbors)):
#print "Found match for "+str(node)+ " in node "+str(sampledNode)
matched = True
break
else:
#print "Replacing "+str(sampledNode)+ " by node "+str(node)
sample.remove(sampledNode)
sample.add(node)
matched = True
break
else:
continue
if (not matched) and (node not in sample):
#print "Adding "+str(node)+" to sample"
sample.add(node)
sampleSize = len(sample)
#print sampleSize
if (sampleSize > lowerbound) and (sampleSize < upperbound):
print "Final size of the sample "+str(sampleSize)
break
else:
print "Discarding sample of size "+str(sampleSize)
continue
return sample
def multiRandomWalk(G_, keptNodes):
picked = []
random.seed(time.clock())
random.shuffle(G_.nodes())
seeds = random.sample(set(G_.nodes()), 5)
sinNodes = int(math.floor(keptNodes/5.0))
for seed in seeds:
current = seed
picked.append(seed)
c = 0.85
temp = 0
num = 1
#print "Added "+str(seed)+ " num is "+str(num)
temp_list = []
num_true = int(100*c)
num_false = 100-num_true
for t_val in range (num_true):
temp_list.append(1)
for f_val in range (num_false):
temp_list.append(0)
while num < sinNodes:
random.shuffle(temp_list)
info_accepted = random.choice(temp_list)
if (info_accepted==1):
neighborlist = G_.neighbors(current)
#prevCurr = current
oneSelected = False
for ind in range(0, len(neighborlist)):
random.seed(time.clock())
random.shuffle(neighborlist)
walkingTo = random.choice(neighborlist)
if (walkingTo not in picked):
num = num+1
temp = num-1
#print "Added "+str(walkingTo)+ " num is "+str(num)
picked.append(walkingTo)
current = walkingTo
oneSelected = True
break
if not oneSelected:
val = temp-1
temp -= 1
current = picked[val]
continue
#temp = temp-1
else:
val = temp-1
temp -= 1
current = picked[val]
continue
return picked