From 4cb6986480def9b0c91fb46e276839c60f96aa49 Mon Sep 17 00:00:00 2001 From: Yigit Sever Date: Sat, 21 Sep 2019 15:06:32 +0300 Subject: Tidy up Wasserstein classes into one file --- Wasserstein_Distance.py | 140 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 Wasserstein_Distance.py (limited to 'Wasserstein_Distance.py') diff --git a/Wasserstein_Distance.py b/Wasserstein_Distance.py new file mode 100644 index 0000000..d2a6408 --- /dev/null +++ b/Wasserstein_Distance.py @@ -0,0 +1,140 @@ +import ot +from sklearn.preprocessing import normalize +from lapjv import lapjv +from sklearn.neighbors import KNeighborsClassifier +from sklearn.metrics import euclidean_distances +from sklearn.externals.joblib import Parallel, delayed +from sklearn.utils import check_array +from sklearn.metrics.scorer import check_scoring +from pathos.multiprocessing import ProcessingPool as Pool +from sklearn.metrics import euclidean_distances +import numpy as np + +class Wasserstein_Matcher(KNeighborsClassifier): + """ + Implements a nearest neighbors classifier for input distributions using the Wasserstein distance as metric. + Source and target distributions are l_1 normalized before computing the Wasserstein distance. + Wasserstein is parametrized by the distances between the individual points of the distributions. + """ + def __init__(self, W_embed, n_neighbors=1, n_jobs=1, verbose=False, sinkhorn= False, sinkhorn_reg=0.1): + """ + Initialization of the class. + Arguments + --------- + W_embed: embeddings of the words, np.array + verbose: True/False + """ + self.sinkhorn = sinkhorn + self.sinkhorn_reg = sinkhorn_reg + self.W_embed = W_embed + self.verbose = verbose + super(Wasserstein_Matcher, self).__init__(n_neighbors=n_neighbors, n_jobs=n_jobs, metric='precomputed', algorithm='brute') + + def _wmd(self, i, row, X_train): + union_idx = np.union1d(X_train[i].indices, row.indices) + W_minimal = self.W_embed[union_idx] + W_dist = euclidean_distances(W_minimal) + bow_i = X_train[i, union_idx].A.ravel() + bow_j = row[:, union_idx].A.ravel() + if self.sinkhorn: + return ot.sinkhorn2(bow_i, bow_j, W_dist, self.sinkhorn_reg, numItermax=50, method='sinkhorn_stabilized',)[0] + else: + return ot.emd2(bow_i, bow_j, W_dist) + + def _wmd_row(self, row): + X_train = self._fit_X + n_samples_train = X_train.shape[0] + return [self._wmd(i, row, X_train) for i in range(n_samples_train)] + + def _pairwise_wmd(self, X_test, X_train=None): + n_samples_test = X_test.shape[0] + + if X_train is None: + X_train = self._fit_X + pool = Pool(nodes=self.n_jobs) # Parallelization of the calculation of the distances + dist = pool.map(self._wmd_row, X_test) + return np.array(dist) + + def fit(self, X, y): # X_train_idf + X = check_array(X, accept_sparse='csr', copy=True) # check if array is sparse + X = normalize(X, norm='l1', copy=False) + return super(Wasserstein_Matcher, self).fit(X, y) # X_train_idf, np_ones(document collection size) + + def predict(self, X): + X = check_array(X, accept_sparse='csr', copy=True) + X = normalize(X, norm='l1', copy=False) + dist = self._pairwise_wmd(X) + dist = dist * 1000 # for lapjv, small floating point numbers are evil + return super(Wasserstein_Matcher, self).predict(dist) + + def kneighbors(self, X, n_neighbors=1): # X : X_train_idf + X = check_array(X, accept_sparse='csr', copy=True) + X = normalize(X, norm='l1', copy=False) + dist = self._pairwise_wmd(X) + dist = dist * 1000 # for lapjv, small floating point numbers are evil + return lapjv(dist) # and here is the matching part + + +class Wasserstein_Retriever(KNeighborsClassifier): + """ + Implements a nearest neighbors classifier for input distributions using the Wasserstein distance as metric. + Source and target distributions are l_1 normalized before computing the Wasserstein distance. + Wasserstein is parametrized by the distances between the individual points of the distributions. + """ + def __init__(self, W_embed, n_neighbors=1, n_jobs=1, verbose=False, sinkhorn= False, sinkhorn_reg=0.1): + """ + Initialization of the class. + Arguments + --------- + W_embed: embeddings of the words, np.array + verbose: True/False + """ + self.sinkhorn = sinkhorn + self.sinkhorn_reg = sinkhorn_reg + self.W_embed = W_embed + self.verbose = verbose + super(Wasserstein_Retriever, self).__init__(n_neighbors=n_neighbors, n_jobs=n_jobs, metric='precomputed', algorithm='brute') + + def _wmd(self, i, row, X_train): + union_idx = np.union1d(X_train[i].indices, row.indices) + W_minimal = self.W_embed[union_idx] + W_dist = euclidean_distances(W_minimal) + bow_i = X_train[i, union_idx].A.ravel() + bow_j = row[:, union_idx].A.ravel() + if self.sinkhorn: + return ot.sinkhorn2(bow_i, bow_j, W_dist, self.sinkhorn_reg, numItermax=50, method='sinkhorn_stabilized',)[0] + else: + return ot.emd2(bow_i, bow_j, W_dist) + + def _wmd_row(self, row): + X_train = self._fit_X + n_samples_train = X_train.shape[0] + return [self._wmd(i, row, X_train) for i in range(n_samples_train)] + + def _pairwise_wmd(self, X_test, X_train=None): + n_samples_test = X_test.shape[0] + + if X_train is None: + X_train = self._fit_X + pool = Pool(nodes=self.n_jobs) # Parallelization of the calculation of the distances + dist = pool.map(self._wmd_row, X_test) + return np.array(dist) + + def fit(self, X, y): + X = check_array(X, accept_sparse='csr', copy=True) + X = normalize(X, norm='l1', copy=False) + return super(Wasserstein_Retriever, self).fit(X, y) + + def predict(self, X): + X = check_array(X, accept_sparse='csr', copy=True) + X = normalize(X, norm='l1', copy=False) + dist = self._pairwise_wmd(X) + return super(Wasserstein_Retriever, self).predict(dist) + + def kneighbors(self, X, n_neighbors=1): + X = check_array(X, accept_sparse='csr', copy=True) + X = normalize(X, norm='l1', copy=False) + dist = self._pairwise_wmd(X) + return super(Wasserstein_Retriever, self).kneighbors(dist, n_neighbors) + + -- cgit v1.2.3-70-g09d2