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Numba implementation of Trustworthiness Score
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import numpy as np | |
import numba | |
from numba import prange | |
#Usage: (X,Y) data | |
#sort_idx,_ = get_first_order_graph(X,n_neighbors=15) | |
#tt = trustworthiness(Y,sort_idx) | |
@numba.jit(nopython=True, parallel=True) | |
def get_first_order_graph(X,n_neighbors): | |
N = X.shape[0] | |
dist = np.zeros((N, N), dtype=np.float32) | |
sort_idx = np.zeros((N,n_neighbors), dtype=np.int32) | |
for i in range(N): | |
#if (i+1)%10000 == 0: | |
# print('Completed ', i+1, ' of ', N) | |
for j in prange(i+1,N): | |
dist[i,j] = np.sum( (X[i]-X[j])**2 ) | |
dist[j,i] = dist[i,j] | |
sort_idx[i,:] = np.argsort(dist[i,:])[1:n_neighbors+1] | |
return sort_idx, dist | |
@numba.jit(nopython=True, parallel=True) | |
def trustworthiness(Y,sort_idx): | |
N = Y.shape[0] | |
K = sort_idx.shape[1] | |
#print(N,K) | |
val = 0.0 | |
for i in prange(N): | |
dist = np.sum((Y - Y[i,:])**2,axis=1) | |
#print(dist.shape) | |
sort_idy = np.argsort(dist)[1:] | |
for j in prange(K): | |
r_0 = np.argwhere(sort_idy==sort_idx[i,j]) | |
#print(i, r_0, sort_idx[i,j]) | |
#print(sort_idy) | |
r = r_0[0,0] | |
#print(i,r) | |
#print(sort_idx[i,j]) | |
#print(sort_idy) | |
r_v = r - K | |
if r_v>0: | |
val += r_v | |
#print(val) | |
val = val * 2 / ( N*K * (2.0*N - 3.0*K - 1.0)) | |
#print(val) | |
return 1 - val |
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