class VSRank(BaseEstimator):
def __init__(self, neighbornum=5, n=5):
print 'vsrank begin'
self.neighbornum = neighbornum
self.similarity = Similarity('COSINE')
self.n = n
def predict(self,testSamples):
recList = []
for user_item in testSamples:
uid = self.dataModel.getUidByUser(user_item[0])
recList.append(self.recommend(uid))
return recList
def fit(self, trainSamples, trainTargets):
self.dataModel = MemeryDataModel(trainSamples, trainTargets, isRating=True)
usersNum = self.dataModel.getUsersNum()
itemsNum = self.dataModel.getItemsNum()
self.T = [{} for i in range(usersNum)]
for uid in range(usersNum):
purchased_items = self.dataModel.getItemIDsFromUid(uid)
for i in range(len(purchased_items)):
for j in range(i+1, len(purchased_items)):
rating_i = self.dataModel.getRating(uid, purchased_items[i])
rating_j = self.dataModel.getRating(uid, purchased_items[j])
if rating_i > rating_j:
key = str(purchased_items[i]) + " " + str(purchased_items[j])
elif rating_i < rating_j:
key = str(purchased_items[j]) + " " + str(purchased_items[i])
else:
continue
self.T[uid][key] = 1
for uid in range(usersNum):
print self.dataModel.getUserByUid(uid), len(self.T[uid])
idf = {}
pair_sum = [[0]*itemsNum for i in range(itemsNum)]
for uid in range(usersNum):
for t, times in self.T[uid].iteritems():
i1, i2 = t.split(" ")
pair_sum[int(i1)][int(i2)] += 1
for i1 in range(itemsNum):
for i2 in range(itemsNum):
if pair_sum[i1][i2] != 0:
key = str(i1) + ' ' + str(i2)
sum = pair_sum[i1][i2] + pair_sum[i2][i1]
alpha = log10(1+9.0*sum/usersNum)
idf[key] = alpha*log2(sum*1.0/pair_sum[i1][i2])+(1-alpha)
W = [{} for i in range(usersNum)]
for uid in range(usersNum):
for t, times in self.T[uid].iteritems():
i1, i2 = t.split(" ")
diff = self.dataModel.getRating(uid, int(i1))-self.dataModel.getRating(uid, int(i2))
tf = log2(1+abs(diff))
W[uid][t] = tf * idf[t]
self.simiMatrix = np.zeros((usersNum, usersNum))
for i in range(usersNum):
for j in range(i+1, usersNum):
s = self.cos(W[i], W[j])
self.simiMatrix[i][j] = self.simiMatrix[j][i] = s
def cos(self, dict1, dict2):
product = 0.0
m1 = 0.0
m2 = 0.0
for k, v in dict1.iteritems():
m1 += v*v
i1, i2 = k.split(' ')
k_ = i2 + ' ' + i1
if dict2.has_key(k):
product += v * dict2[k]
elif dict2.has_key(k_):
product -= v * dict2[k_]
for k, v in dict2.iteritems():
m2 += v*v
if product == 0:
return 0
else:
return product/sqrt(m1)/sqrt(m2)
def tau(self, dict1, dict2, u1, u2):
pass
def neighborhood(self, userID):
neighbors = np.argsort(np.array(self.simiMatrix[userID]))[-1:-self.neighbornum-1:-1]
return neighbors
def predict_single(self, userID, itemID):
rating = 0.0
for uid in self.neighborhood(userID):
if itemID in self.dataModel.getItemIDsFromUid(uid):
rating += self.simiMatrix[userID][uid] * self.dataModel.getRating(uid, itemID)
return rating
def recommend(self, u):
userID = self.dataModel.getUidByUser(u)
if userID == -1:
print 'not in test'
return []
else:
# return self.recommend_listwise(userID)
return self.recommend_pairwise(userID)
def recommend_pointwise(self, userID):
#interactedItems = self.dataModel.getItemIDsFromUid(userID)
ratings = dict()
for uid in self.neighborhood(userID):
for iid in self.dataModel.getItemIDsFromUid(uid):
#if iid in interactedItems:
#continue
r = ratings.get(iid, 0)
ratings[iid] = r + self.simiMatrix[userID][uid] * self.dataModel.getRating(uid, iid)
r = [x for (x, y) in sorted(ratings.items(), lambda a, b: cmp(a[1], b[1]), reverse=True)[:self.n]]
return [self.dataModel.getItemByIid(i) for i in r]
def recommend_pairwise(self, userID):
itemsNum = self.dataModel.getItemsNum()
N = itemsNum
recNum = self.n
pi = [0]*itemsNum
rank = []
for i in range(itemsNum):
sum1 = 0
sum2 = 0
for j in range(itemsNum):
if j != i:
p = self.preference(userID, i, j)
sum1 += p
sum2 -= p
pi[i] = sum1 - sum2
I = set(i for i in range(itemsNum))
while recNum > 0:
# while len(I) > 0:
recNum -= 1
t = np.argmax(pi)
rank.append(t)
I.remove(t)
pi[t] = None
for i in I:
pi[i] += self.preference(userID, t, i) - self.preference(userID, i, t)
# r = [x for (x, y) in sorted(zip(range(itemsNum), rank), lambda a, b: cmp(a[1], b[1]))[:self.n]]
return [self.dataModel.getItemByIid(i) for i in rank]
def preference(self, uid, i1, i2):
nerghborhood = []
keystr = str(i1) + ' ' + str(i2)
keystr_ = str(i2) + ' ' + str(i1)
for i in range(self.dataModel.getUsersNum()):
if self.T[i].has_key(keystr) or self.T[i].has_key(keystr_):
nerghborhood.append(i)
distance = [0]*len(nerghborhood)
for i in range(len(nerghborhood)):
distance[i] = self.simiMatrix[uid][nerghborhood[i]]
nerghborhood = [x for (x, y) in sorted(zip(nerghborhood, distance), lambda a, b: cmp(a[1], b[1]), reverse=True)[:self.neighbornum]]
preference = 0.0
sum = 0.0
for i in nerghborhood:
rating1 = self.dataModel.getRating(i, i1)
rating2 = self.dataModel.getRating(i, i2)
sum += self.simiMatrix[uid][i]
if rating1 > rating2:
preference += self.simiMatrix[uid][i]
elif rating1 < rating2:
preference -= self.simiMatrix[uid][i]
if sum == 0:
return 0
else:
return preference/sum
def recommend_listwise(self, userID):
itemsNum = self.dataModel.getItemsNum()
M = [[0]*itemsNum for i in range(itemsNum)]
for uid in self.neighborhood(userID):
for t, times in self.T[uid].iteritems():
i1, i2 = t.split(" ")
M[int(i1)][int(i2)] += 1
for m in xrange(itemsNum):
for n in xrange(itemsNum):
for k in xrange(itemsNum):
M[n][k] = max(M[n][k], min(M[n][m], M[m][k]))
rank = [0]*itemsNum
for m in range(itemsNum):
for n in range(itemsNum):
if n != m and M[m][n] > M[n][m]:
rank[m] += 1
r = [x for (x, y) in sorted(zip(range(itemsNum), rank), lambda a, b: cmp(a[1], b[1]))[:self.n]]
return [self.dataModel.getItemByIid(i) for i in r]
def score(self, testSamples, trueLabels):
print 'vsrank scoring ...'
#print len(testSamples)
trueList = []
recommendList= []
user_unique = list(set(np.array(testSamples)[:,0]))
for u in user_unique:
uTrueIndex = np.argwhere(np.array(testSamples)[:,0] == u)[:,0]
#true = [self.dataModel.getIidByItem(i) for i in list(np.array(testSamples)[uTrueIndex][:,1])]
uTrueItem = list(np.array(testSamples)[uTrueIndex][:,1])
uTrueRating = list(np.array(trueLabels)[uTrueIndex])
true = [x for (x, y) in sorted(zip(uTrueItem, uTrueRating), lambda a, b: cmp(a[1], b[1]), reverse=True)[:self.n]]
trueList.append(true)
pre = self.recommend(u)
recommendList.append(pre)
e = Eval()
result = e.evalAll(recommendList, trueList)
print 'vsrank result:'+'('+str(self.get_params())+')'+str(result)
return (result)['F1']
