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EKMeans.py
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EKMeans.py
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import numpy as np
from scipy.optimize import minimize
from scipy.stats import beta
class EKMeans(object):
#constructor - has user choice parameters
def __init__(self, epsilon = .001, sharpness = .1, tol = .0001, max_iter=50, noise_tol =4, one_clust_test=True):
self.epsilon = epsilon
self.sharpness = sharpness
self.tolerance = tol
self.max_iter = max_iter
self.noise_tol = noise_tol
self.one_clust_test = one_clust_test
#attributes - user does not set
self.reset_obj()
def reset_obj(self):
self.cluster_centers_ = []
self.labels_ = None
self.n_centers_ = 0
self.noise_row_drops = []
self.inertia_ =0
self.gap_stat_ = 0
#fit routine
def fit(self,A):
self.reset_obj()
#1. Create the Matrix L = D ^ -.5 * A * D^-.5; D = diagonal matrix that is sum of rows in A
D = np.diag(np.sum(A, axis=1))
D_power = D**-.5
D_power[D_power == np.inf] = 0
L = np.dot(D_power,np.dot(A,D_power))
#1. Compute the EigenVectors and Values of L
#print L.shape
e_vals, e_vecs = np.linalg.eigh(L)
#2. Get Reverse Sorted Order - largest to smallest
e_order = np.argsort(e_vals)[::-1]
one_c_fit = 10**10
if len(e_vals) ==1:
self.labels_ = np.zeros(1)
return self.labels_
if self.one_clust_test == True:
self.one_clust_fit_alt(e_vecs, e_order)
one_c_fit = self.gap_stat_
flag =1
last_loop=0
while flag:
origin_pts = [[1]]
centers = []
#run fit routine as long as there are points clustered at O
while origin_pts and len(centers)<len(e_order):
eig_vecs_matrix, centers = self.initialize_fit(e_vecs, e_order, centers)
centers, classified = self.k_iter(centers, eig_vecs_matrix)
#print eig_vecs_matrix
if len(centers) -1 in classified:
origin_pts = classified[len(centers)-1]
else:
origin_pts = []
tol_runs =0
if last_loop !=1:
contd = 0
while tol_runs < self.noise_tol and len(centers) <= len(e_order):
if contd ==1:
tol_runs +=1
continue
eig_vecs_matrix, centers = self.initialize_fit(e_vecs, e_order, centers)
#eig_vecs_matrix = np.delete(eig_vecs_matrix, self.noise_row_drops, 0)
centers, classified = self.k_iter(centers, eig_vecs_matrix)
#print classified
if len(centers) -1 in classified:
bad_vecs = classified[len(centers)-1]
bad_inds = self.ret_bad_inds(bad_vecs, e_vecs,e_order, centers)
self.noise_row_drops.extend(bad_inds)
contd=1
continue
tol_runs +=1
last_loop =1
else:
self.final_fit(centers,e_vecs, e_order)
flag = 0
if one_c_fit < self.gap_stat_:
last_mult = self.gap_stat_
last_one = one_c_fit
ref_mult, ref_sing = self.reference_sim( A, classified,self.labels_)
adj_mult = ref_mult - last_mult
adj_one = ref_sing - last_one
if adj_one< adj_mult:
self.one_clust_fit_alt(e_vecs, e_order)
else:
self.one_clust_test = False
self.fit(A)
self.one_clust_test = True
return self.labels_
def ret_bad_inds(self,bad_vecs, e_vecs, e_order, centers):
bad_inds = []
eig_vecs_matrix = np.transpose(np.array([e_vecs[:,e_order[o]] for o in range(0,len(centers)-1) ]))
for n in range(0,eig_vecs_matrix.shape[0]):
v = eig_vecs_matrix[n,:]
if any((v == a).all() for a in bad_vecs):
bad_inds.append(n)
return bad_inds
def final_fit(self,centers,e_vecs, e_order):
#print centers
centers = centers[:len(centers)-1]
#print centers
q =len(centers)
#print q
center_classes = [np.dot(c,c) > self.epsilon for c in centers]
m_s = [self.e_dist_constants(c) for c in centers]
eig_vecs_matrix = np.transpose(np.array([e_vecs[:,e_order[o]] for o in range(0,q) ]))
classified = self.classify_pts(eig_vecs_matrix, centers, center_classes, m_s)
#print classified
labels = self.set_labels(classified,eig_vecs_matrix)
#print classified
self.inertia_,self.gap_stat_ = self.fit_quality(classified,centers,labels)
self.labels_ = np.array(labels)
self.n_centers_ = len(set(labels))
self.cluster_centers_ =centers
return
def set_labels(self,classified, eig_vecs_matrix):
labels = []
for i in range(0,eig_vecs_matrix.shape[0]):
x = eig_vecs_matrix[i,:]
for c in classified.keys():
listy = classified[c]
if any((x == a).all() for a in listy):
labels.append(c)
return labels
def k_iter(self,centers, eig_vecs_matrix ):
mov = 1
classified = dict()
iterations = 0
while (mov > self.tolerance) and (iterations < self.max_iter):
#1. classify the centers as near or far away from origin
center_classes = [np.dot(c,c) > self.epsilon for c in centers]
m_s = [self.e_dist_constants(c) for c in centers]
#2. classify the center belonging to each x
#looks like classified[center index in list] = list of x's
classified = self.classify_pts(eig_vecs_matrix, centers, center_classes, m_s)
new_centers = self.new_center_calc(classified,centers)
#4. Calculate maximum movement
mov = max([self.or_dist(centers[i],new_centers[i]) for i in range(0,len(centers))])
centers = new_centers
iterations +=1
return centers,classified
def classify_pts(self, eig_vecs_matrix, centers, center_classes, m_s):
classified = dict()
for i in range(0,eig_vecs_matrix.shape[0]):
x = eig_vecs_matrix[i,:]
#print eig_vecs_matrix.shape[0]
closest_center = self.closest(x,centers,center_classes, m_s)
if closest_center in classified:
classified[closest_center].append(x)
else:
classified[closest_center] = [x]
return classified
def new_center_calc(self,classified, centers):
new_centers = []
for k in range(0,len(centers)):
if k in classified:
new_centers.append(np.mean(np.array(classified[k]),axis=0))
else:
#unsure about this - not changing center vs setting center to origin
new_centers.append(centers[k])
return new_centers
def closest(self,x,centers, center_classes, m_s):
closest_dist = 10**9
chosen = 0
for ind in range(0,len(centers)):
center = centers[ind]
#print "Center is ", center
center_class = center_classes[ind]
if center_class ==1:
dist = self.e_dist(x,center, m_s[ind])
#print "E-dist is", dist
else:
dist = self.or_dist(x,center)
#print "OR-dist is", dist
if dist < closest_dist:
chosen = ind
closest_dist = dist
#print "Chosen Ind is", chosen
return chosen
def e_dist(self,x,c, M):
x_minus_c = np.array([np.array(x) - np.array(c)])
return np.dot(x_minus_c,np.dot(M,x_minus_c.T))
def e_dist_constants(self,c):
cT_c = np.dot(np.array(c),np.array(c))
c_cT = np.dot(np.array([np.array(c)]).T, np.array([np.array(c)]))
M = (1/self.sharpness) * (np.identity(len(c)) - (1/cT_c)* c_cT ) + (self.sharpness/cT_c)* c_cT
return M
def or_dist(self,x,c):
return np.linalg.norm(np.array(x)-np.array(c))
def initialize_fit(self,e_vecs, e_order,centers):
if not centers:
curr_centroids = 2
#print e_vecs
eig_vecs_matrix = np.transpose(np.array([e_vecs[:,e_order[o]] for o in range(0,curr_centroids) ]))
eig_vecs_matrix = np.delete(eig_vecs_matrix, self.noise_row_drops, 0)
#Last center is always initialized at the origin
c3 = np.zeros(curr_centroids)
#c1 is initialized at the piont that is furthest away from the origin
c1 = np.zeros(curr_centroids)
for n in range(0,eig_vecs_matrix.shape[0]):
v = eig_vecs_matrix[n,:]
if np.linalg.norm(v) > np.linalg.norm(c1):
c1 = v
#c2 is initialized at the point that simultaneously maximizes its norm while
#minimizing the dot product with c1
c2 = np.zeros(curr_centroids)
for n in range(0,eig_vecs_matrix.shape[0]):
small = .000000000001
v = eig_vecs_matrix[n,:]
if np.linalg.norm(v) / np.sqrt(max(np.dot(c1,v),small)) > np.linalg.norm(c2)/ np.sqrt(max(np.dot(c1,c2),small)):
c2 = v
centers.extend([c1,c2,c3])
else:
centers = [np.append(c, 0) for c in centers]
curr_centroids = len(centers)
eig_vecs_matrix = np.transpose(np.array([e_vecs[:,e_order[o]] for o in range(0,curr_centroids) ]))
eig_vecs_matrix = np.delete(eig_vecs_matrix, self.noise_row_drops, 0)
centers.append(np.zeros(curr_centroids))
return eig_vecs_matrix, centers
def e_dist_alt(self,x,c):
cT_c = np.dot(np.array(c),np.array(c))
c_cT = np.dot(np.array([np.array(c)]).T, np.array([np.array(c)]))
M = (1/self.sharpness) * (np.identity(len(c)) - (1/cT_c)* c_cT ) + (self.sharpness/cT_c)* c_cT
x_minus_c = np.array([np.array(x) - np.array(c)])
return np.dot(x_minus_c,np.dot(M,x_minus_c.T))
def fit_quality(self,classified,centers,labels):
center_classes = [np.dot(c,c) > self.epsilon for c in centers]
m_s = [self.e_dist_constants(c) for c in centers]
inertia=0
W_k = 0
for i in classified.keys():
D_r = 0
if i in classified:
x_s = classified[i]
else:
x_s = []
n_r = len(x_s)
for k in range(0,len(x_s)):
x1 = x_s[k]
if center_classes[i] ==1:
inertia += self.e_dist(x1,centers[i], m_s[i])
else:
inertia += self.or_dist(x1,centers[i])
for j in range(0,k):
x2 = x_s[j]
if center_classes[i] ==1:
D_r+= self.e_dist_alt(x1,x2)**2
D_r+= self.e_dist_alt(x2,x1)**2
else:
D_r+= self.or_dist(x1,x2)**2
D_r+= self.or_dist(x2,x1)**2
D_r = float(D_r)/(2*n_r)
W_k += D_r
#print classified
#print classified #classifiedprint classified
return inertia, W_k
def one_clust_fit_alt(self,e_vecs, e_order):
eig_vecs_matrix = np.transpose(np.array([e_vecs[:,e_order[o]] for o in range(0,1) ]))
#eig_vecs_matrix = np.delete(eig_vecs_matrix, self.noise_row_drops, 0)
c2 = np.zeros(1)
c1 = np.zeros(1)
for n in range(0,eig_vecs_matrix.shape[0]):
v = eig_vecs_matrix[n,:]
if np.linalg.norm(v) > np.linalg.norm(c1):
c1 = v
centers=[c1,c2]
centers,classified = self.k_iter(centers, eig_vecs_matrix )
if len(centers) -1 in classified:
return False
else:
self.labels_ = np.zeros(eig_vecs_matrix.shape[0])
self.inertia_,self.gap_stat_=self.fit_quality(classified,centers,self.labels_)
self.n_centers_ = 1
return True
def reference_sim(self, A, classified,labels):
num_centers = len(set(labels))
small = .0000000000001
ideal_A = np.zeros([A.shape[0],A.shape[1]])
for i in range(0,len(labels)):
for j in range(0,i+1):
if labels[i] == labels[j]:
ideal_A[i,j] = 1
ideal_A[j,i] = 1
pred_pos = A[ideal_A ==1]
pred_neg = A[ideal_A ==0]
pos_a,pos_b,pos_loc, pos_scale= beta.fit(pred_pos)
neg_a,neg_b,neg_loc, neg_scale= beta.fit(pred_neg)
fits = []
#Fit comparison iwth more than 1 clust
for sim in range(0, 50):
simulated_mat = np.ones([A.shape[0],A.shape[1]])
for i in range(0,len(labels)):
for j in range(0,i):
if ideal_A[i,j] ==0:
simulated_mat[i,j] = simulated_mat[j,i]= beta.rvs(max(neg_a,small), max(small,neg_b), loc=neg_loc,scale =neg_scale)
else:
simulated_mat[i, j ] = simulated_mat[j, i ] = beta.rvs(max(pos_a,small), max(small,pos_b), loc=pos_loc,scale =pos_scale)
self.one_clust_test = False
whereAreNaNs = np.isnan(simulated_mat)
simulated_mat[whereAreNaNs] = 0
self.fit(simulated_mat)
#print simulated_mat
fits.append(self.gap_stat_)
multi_fit = np.mean(fits)
fits_one = []
pos_a,pos_b,pos_loc, pos_scale= beta.fit(A)
for sim in range(0, 50):
simulated_mat = np.ones([A.shape[0],A.shape[1]])
for i in range(0,len(labels)):
for j in range(0,i):
simulated_mat[i,j] = simulated_mat[j,i]= beta.rvs(max(small,pos_a), max(small,pos_b), loc=pos_loc,scale =pos_scale)
whereAreNaNs = np.isnan(simulated_mat)
simulated_mat[whereAreNaNs] = 0
e_vals, e_vecs = np.linalg.eigh(simulated_mat)
#2. Get Reverse Sorted Order - largest to smallest
e_order = np.argsort(e_vals)[::-1]
self.one_clust_fit_alt(e_vecs,e_order)
fits_one.append(self.gap_stat_)
one_fit = np.mean(fits_one)
return multi_fit, one_fit