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+# This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
+# See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
+# Author(s): Yuichi Ike, Raphaƫl Tinarrage
+#
+# Copyright (C) 2020 Inria, Copyright (C) 2020 FUjitsu Laboratories Ltd.
+#
+# Modification(s):
+# - YYYY/MM Author: Description of the modification
+
+
+from gudhi.weighted_rips_complex import WeightedRipsComplex
+from gudhi.point_cloud.dtm import DistanceToMeasure
+from scipy.spatial.distance import cdist
+
+class DTMRipsComplex(WeightedRipsComplex):
+ """
+ Class to generate a DTM Rips complex from a distance matrix or a point set,
+ in the way described in :cite:`dtmfiltrations`.
+ Remark that all the filtration values are doubled compared to the definition in the paper
+ for the consistency with RipsComplex.
+ :Requires: `SciPy <installation.html#scipy>`_
+ """
+ def __init__(self,
+ points=None,
+ distance_matrix=None,
+ k=1,
+ q=2,
+ max_filtration=float('inf')):
+ """
+ Args:
+ points (numpy.ndarray): array of points.
+ distance_matrix (numpy.ndarray): full distance matrix.
+ k (int): number of neighbors for the computation of DTM. Defaults to 1, which is equivalent to the usual Rips complex.
+ q (float): order used to compute the distance to measure. Defaults to 2.
+ max_filtration (float): specifies the maximal filtration value to be considered.
+ """
+ if distance_matrix is None:
+ if points is None:
+ # Empty Rips construction
+ points=[]
+ distance_matrix = cdist(points,points)
+ self.distance_matrix = distance_matrix
+
+ # TODO: address the error when k is too large
+ if k <= 1:
+ self.weights = [0] * len(distance_matrix)
+ else:
+ dtm = DistanceToMeasure(k, q=q, metric="precomputed")
+ self.weights = dtm.fit_transform(distance_matrix)
+ self.max_filtration = max_filtration
+