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-rw-r--r--CMakeLists.txt1
-rw-r--r--biblio/bibliography.bib22
-rw-r--r--data/persistence_diagram/PD1.pers3
-rw-r--r--data/persistence_diagram/PD2.pers2
-rw-r--r--src/CMakeLists.txt1
-rw-r--r--src/Doxyfile3
-rw-r--r--src/Kernels/doc/COPYRIGHT19
-rw-r--r--src/Kernels/doc/Intro_kernels.h108
-rw-r--r--src/Kernels/example/CMakeLists.txt10
-rw-r--r--src/Kernels/example/kernel.txt8
-rw-r--r--src/Kernels/example/kernel_basic_example.cpp65
-rw-r--r--src/Kernels/include/gudhi/kernel.h365
-rw-r--r--src/Kernels/test/CMakeLists.txt12
-rw-r--r--src/Kernels/test/test_kernel.cpp56
-rw-r--r--src/Persistence_representations/example/persistence_weighted_gaussian.cpp96
-rw-r--r--src/Persistence_representations/example/sliced_wasserstein.cpp55
-rw-r--r--src/Persistence_representations/include/gudhi/Persistence_weighted_gaussian.h143
-rw-r--r--src/Persistence_representations/include/gudhi/Sliced_Wasserstein.h285
-rw-r--r--src/cmake/modules/GUDHI_modules.cmake4
19 files changed, 1255 insertions, 3 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 10373f75..b28dcbf2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,6 +50,7 @@ add_gudhi_module(Subsampling)
add_gudhi_module(Tangential_complex)
add_gudhi_module(Witness_complex)
add_gudhi_module(Nerve_GIC)
+add_gudhi_module(Kernels)
message("++ GUDHI_MODULES list is:\"${GUDHI_MODULES}\"")
diff --git a/biblio/bibliography.bib b/biblio/bibliography.bib
index b101cb76..e56734e4 100644
--- a/biblio/bibliography.bib
+++ b/biblio/bibliography.bib
@@ -1072,3 +1072,25 @@ language={English}
+
+@InProceedings{pmlr-v70-carriere17a,
+ title = {Sliced {W}asserstein Kernel for Persistence Diagrams},
+ author = {Mathieu Carri{\`e}re and Marco Cuturi and Steve Oudot},
+ booktitle = {Proceedings of the 34th International Conference on Machine Learning},
+ pages = {664--673},
+ year = {2017},
+ editor = {Doina Precup and Yee Whye Teh},
+ volume = {70},
+ series = {Proceedings of Machine Learning Research},
+ address = {International Convention Centre, Sydney, Australia},
+ month = {06--11 Aug},
+ publisher = {PMLR},
+}
+
+@INPROCEEDINGS{Rahimi07randomfeatures,
+ author = {Ali Rahimi and Ben Recht},
+ title = {Random features for large-scale kernel machines},
+ booktitle = {In Neural Information Processing Systems},
+ year = {2007}
+}
+
diff --git a/data/persistence_diagram/PD1.pers b/data/persistence_diagram/PD1.pers
new file mode 100644
index 00000000..404199b4
--- /dev/null
+++ b/data/persistence_diagram/PD1.pers
@@ -0,0 +1,3 @@
+2.7 3.7
+9.6 14
+34.2 34.974 \ No newline at end of file
diff --git a/data/persistence_diagram/PD2.pers b/data/persistence_diagram/PD2.pers
new file mode 100644
index 00000000..125d8e4b
--- /dev/null
+++ b/data/persistence_diagram/PD2.pers
@@ -0,0 +1,2 @@
+2.8 4.45
+9.5 14.1 \ No newline at end of file
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 94587044..0ae26081 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -26,6 +26,7 @@ add_gudhi_module(Subsampling)
add_gudhi_module(Tangential_complex)
add_gudhi_module(Witness_complex)
add_gudhi_module(Nerve_GIC)
+add_gudhi_module(Kernels)
message("++ GUDHI_MODULES list is:\"${GUDHI_MODULES}\"")
diff --git a/src/Doxyfile b/src/Doxyfile
index f1981e2e..2348b290 100644
--- a/src/Doxyfile
+++ b/src/Doxyfile
@@ -854,7 +854,8 @@ IMAGE_PATH = doc/Skeleton_blocker/ \
doc/Tangential_complex/ \
doc/Bottleneck_distance/ \
doc/Nerve_GIC/ \
- doc/Persistence_representations/
+ doc/Persistence_representations/ \
+ doc/Kernels/
# The INPUT_FILTER tag can be used to specify a program that doxygen should
# invoke to filter for each input file. Doxygen will invoke the filter program
diff --git a/src/Kernels/doc/COPYRIGHT b/src/Kernels/doc/COPYRIGHT
new file mode 100644
index 00000000..0c36a526
--- /dev/null
+++ b/src/Kernels/doc/COPYRIGHT
@@ -0,0 +1,19 @@
+The files of this directory are part of the Gudhi Library. The Gudhi library
+(Geometric Understanding in Higher Dimensions) is a generic C++ library for
+computational topology.
+
+Author(s): Mathieu Carrière
+
+Copyright (C) 2017 INRIA
+
+This program is free software: you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation, either version 3 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program. If not, see <http://www.gnu.org/licenses/>.
diff --git a/src/Kernels/doc/Intro_kernels.h b/src/Kernels/doc/Intro_kernels.h
new file mode 100644
index 00000000..163690b1
--- /dev/null
+++ b/src/Kernels/doc/Intro_kernels.h
@@ -0,0 +1,108 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Author(s): Mathieu Carriere
+ *
+ * Copyright (C) 2017 INRIA
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DOC_KERNEL_INTRO_KERNEL_H_
+#define DOC_KERNEL_INTRO_KERNEL_H_
+
+namespace Gudhi {
+
+namespace kernel {
+
+/** \defgroup kernel Kernels
+ *
+ * \author Mathieu Carrière
+ *
+ * @{
+ *
+ * Kernels are generalized scalar products. They take the form of functions whose evaluations on pairs of persistence diagrams are equal
+ * to the scalar products of the images of the diagrams under some feature map into a (generally unknown and infinite dimensional)
+ * Hilbert space. Kernels are
+ * very useful to handle any type of data for algorithms that require at least a Hilbert structure, such as Principal Component Analysis
+ * or Support Vector Machines. In this package, we implement three kernels for persistence diagrams:
+ * the Persistence Scale Space Kernel (PSSK)---see \cite Reininghaus_Huber_ALL_PSSK,
+ * the Persistence Weighted Gaussian Kernel (PWGK)---see \cite Kusano_Fukumizu_Hiraoka_PWGK,
+ * and the Sliced Wasserstein Kernel (SWK)---see \cite pmlr-v70-carriere17a.
+ *
+ * \section pwg Persistence Weighted Gaussian Kernel and Persistence Scale Space Kernel
+ *
+ * The PWGK is built with Gaussian Kernel Mean Embedding, meaning that each persistence diagram is first
+ * sent to the Hilbert space of a Gaussian kernel with bandwidth parameter \f$\sigma >0\f$ using a weighted mean embedding \f$\Phi\f$:
+ *
+ * \f$ \Phi\,:\,D\,\rightarrow\,\sum_{p\in D}\,w(p)\,{\rm exp}\left(-\frac{\|p-\cdot\|_2^2}{2\sigma^2}\right) \f$,
+ *
+ * Usually, the weight function is chosen to be an arctan function of the distance of the point to the diagonal:
+ * \f$w(p) = {\rm arctan}(C\,|y-x|^\alpha)\f$, for some parameters \f$C,\alpha >0\f$.
+ * Then, either their scalar product in this space is
+ * computed (Linear Persistence Weighted Gaussian Kernel):
+ *
+ * \f$ LPWGK(D_1,D_2)=\langle\Phi(D_1),\Phi(D_2)\rangle
+ * \,=\,\sum_{p\in D_1}\,\sum_{q\in D_2}\,w(p)\,w(q)\,{\rm exp}\left(-\frac{\|p-q\|_2^2}{2\sigma^2}\right)\f$,
+ *
+ * or a second Gaussian kernel with bandwidth parameter \f$\tau >0\f$ is applied to their distance in this space
+ * (Gaussian Persistence Weighted Gaussian Kernel):
+ *
+ * \f$ GPWGK(D_1,D_2)={\rm exp}\left(-\frac{\|\Phi(D_1)-\Phi(D_2)\|^2}{2\tau^2} \right)\f$,
+ * where \f$\|\Phi(D_1)-\Phi(D_2)\|^2 = \langle\Phi(D_1)-\Phi(D_2),\Phi(D_1)-\Phi(D_2)\rangle\f$.
+ *
+ * It follows that the computation time is \f$O(n^2)\f$ where \f$n\f$ is the number of points
+ * in the diagrams. This time can be improved by computing approximations of the kernel
+ * with \f$m\f$ Fourier features \cite Rahimi07randomfeatures. In that case, the computation time becomes \f$O(mn)\f$.
+ *
+ * The PSSK is a Linear Persistence Weighted Gaussian Kernel between modified diagrams:
+ * the symmetric of each point with respect to the diagonal is first added in each diagram, and then the weight function
+ * is set to be +1 if the point is above the diagonal and -1 otherwise.
+ *
+ * \section sw Sliced Wasserstein Kernel
+ *
+ * The Sliced Wasserstein Kernel is defined as a Gaussian-like Kernel between persistence diagrams, where the distance used for
+ * comparison is the Sliced Wasserstein distance \f$SW\f$ between persistence diagrams, defined as the integral of the 1-norm
+ * between the sorted projections of the diagrams onto all lines passing through the origin:
+ *
+ * \f$ SW(D_1,D_2)=\int_{\theta\in\mathbb{S}}\,\|\pi_\theta(D_1\cup\pi_\Delta(D_2))-\pi_\theta(D_2\cup\pi_\Delta(D_1))\|_1{\rm d}\theta\f$,
+ *
+ * where \f$\pi_\theta\f$ is the projection onto the line defined with angle \f$\theta\f$ in the unit circle \f$\mathbb{S}\f$,
+ * and \f$\pi_\Delta\f$ is the projection onto the diagonal.
+ * The integral can be either computed exactly in \f$O(n^2{\rm log}(n))\f$ time, where \f$n\f$ is the number of points
+ * in the diagrams, or approximated by sampling \f$m\f$ lines in the circle in \f$O(mn{\rm log}(n))\f$ time. The SWK is then computed as:
+ *
+ * \f$ SWK(D_1,D_2) = {\rm exp}\left(-\frac{SW(D_1,D_2)}{2\sigma^2}\right).\f$
+ *
+ * When launching:
+ *
+ * \code $> ./BasicEx ../../../../data/persistence_diagram/PD1 ../../../../data/persistence_diagram/PD2
+ * \endcode
+ *
+ * the program output is:
+ *
+ * \include Kernels/kernel.txt
+ *
+ *
+ * \copyright GNU General Public License v3.
+ * \verbatim Contact: gudhi-users@lists.gforge.inria.fr \endverbatim
+ */
+/** @} */ // end defgroup kernel
+
+} // namespace kernel
+
+} // namespace Gudhi
+
+#endif // DOC_KERNEL_INTRO_KERNEL_H_
diff --git a/src/Kernels/example/CMakeLists.txt b/src/Kernels/example/CMakeLists.txt
new file mode 100644
index 00000000..d8ad4b42
--- /dev/null
+++ b/src/Kernels/example/CMakeLists.txt
@@ -0,0 +1,10 @@
+cmake_minimum_required(VERSION 2.6)
+project(Kernels_examples)
+
+add_executable ( BasicEx kernel_basic_example.cpp )
+
+if (TBB_FOUND)
+ target_link_libraries(BasicEx ${TBB_LIBRARIES})
+endif()
+
+add_test(NAME Kernels_example_basicex COMMAND $<TARGET_FILE:BasicEx> "${CMAKE_SOURCE_DIR}/data/persistence_diagram/PD1" "${CMAKE_SOURCE_DIR}/data/persistence_diagram/PD2") \ No newline at end of file
diff --git a/src/Kernels/example/kernel.txt b/src/Kernels/example/kernel.txt
new file mode 100644
index 00000000..5fb8b504
--- /dev/null
+++ b/src/Kernels/example/kernel.txt
@@ -0,0 +1,8 @@
+SWK exact = 0.875446
+SWK approx = 0.875204
+PSSK exact = 0.0218669
+PSSK approx = 0.0213766
+LPWGK exact = 2.57351
+LPWGK approx = 2.49102
+GPWGK exact = 0.98783
+GPWGK approx = 0.987591 \ No newline at end of file
diff --git a/src/Kernels/example/kernel_basic_example.cpp b/src/Kernels/example/kernel_basic_example.cpp
new file mode 100644
index 00000000..7ecbe401
--- /dev/null
+++ b/src/Kernels/example/kernel_basic_example.cpp
@@ -0,0 +1,65 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Authors: Mathieu Carrière
+ *
+ * Copyright (C) 2017 INRIA
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gudhi/kernel.h>
+#include <iostream>
+#include <string>
+#include <fstream>
+#include <sstream>
+
+
+void usage(int nbArgs, char *const progName) {
+ std::cerr << "Error: Number of arguments (" << nbArgs << ") is not correct\n";
+ std::cerr << "Usage: " << progName << " PD1 PD2 \n";
+ std::cerr << " i.e.: " << progName << " ../../../../data/persistence_diagram/PD1.pers ../../../../data/persistence_diagram/PD2.pers \n";
+ exit(-1); // ----- >>
+}
+
+int main(int argc, char **argv) {
+
+ if (argc != 3) usage(argc, argv[0]);
+
+ double sigma = 2; double tau = 5;
+
+ std::string PDname1(argv[1]); std::string PDname2(argv[2]);
+ std::vector< std::pair<double, double> > v1, v2; std::string line; double b,d;
+
+ std::ifstream input1(PDname1);
+ while(std::getline(input1,line)){
+ std::stringstream stream(line); stream >> b; stream >> d; v1.push_back(std::pair<double,double>(b,d));
+ }
+
+ std::ifstream input2(PDname2);
+ while(std::getline(input2,line)){
+ std::stringstream stream(line); stream >> b; stream >> d; v2.push_back(std::pair<double,double>(b,d));
+ }
+
+ std::cout << "SWK exact = " << Gudhi::kernel::sliced_wasserstein_kernel (v1,v2,sigma,-1) << std::endl;
+ std::cout << "SWK approx = " << Gudhi::kernel::sliced_wasserstein_kernel (v1,v2,sigma) << std::endl;
+ std::cout << "PSSK exact = " << Gudhi::kernel::persistence_scale_space_kernel (v1,v2,sigma,-1) << std::endl;
+ std::cout << "PSSK approx = " << Gudhi::kernel::persistence_scale_space_kernel (v1,v2,sigma) << std::endl;
+ std::cout << "LPWGK exact = " << Gudhi::kernel::linear_persistence_weighted_gaussian_kernel (v1,v2,sigma,Gudhi::kernel::arctan_weight,-1) << std::endl;
+ std::cout << "LPWGK approx = " << Gudhi::kernel::linear_persistence_weighted_gaussian_kernel (v1,v2,sigma,Gudhi::kernel::arctan_weight) << std::endl;
+ std::cout << "GPWGK exact = " << Gudhi::kernel::gaussian_persistence_weighted_gaussian_kernel (v1,v2,sigma,tau,Gudhi::kernel::arctan_weight,-1) << std::endl;
+ std::cout << "GPWGK approx = " << Gudhi::kernel::gaussian_persistence_weighted_gaussian_kernel (v1,v2,sigma,tau,Gudhi::kernel::arctan_weight) << std::endl;
+
+}
diff --git a/src/Kernels/include/gudhi/kernel.h b/src/Kernels/include/gudhi/kernel.h
new file mode 100644
index 00000000..3293cc62
--- /dev/null
+++ b/src/Kernels/include/gudhi/kernel.h
@@ -0,0 +1,365 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Author(s): Mathieu Carrière
+ *
+ * Copyright (C) 2018 INRIA (France)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef KERNEL_H_
+#define KERNEL_H_
+
+#include <cstdlib>
+#include <vector>
+#include <algorithm>
+#include <cmath>
+#include <random>
+#include <limits> //for numeric_limits<>
+#include <utility> //for pair<>
+
+#include <boost/math/constants/constants.hpp>
+
+
+namespace Gudhi {
+namespace kernel {
+
+using PD = std::vector<std::pair<double,double> >;
+double pi = boost::math::constants::pi<double>();
+
+
+
+
+// ********************************************************************
+// Utils.
+// ********************************************************************
+
+bool sortAngle(const std::pair<double, std::pair<int,int> >& p1, const std::pair<double, std::pair<int,int> >& p2){return (p1.first < p2.first);}
+bool myComp(const std::pair<int,double> & P1, const std::pair<int,double> & P2){return P1.second < P2.second;}
+
+double pss_weight(std::pair<double,double> P){
+ if(P.second > P.first) return 1;
+ else return -1;
+}
+
+double arctan_weight(std::pair<double,double> P){
+ return atan(P.second - P.first);
+}
+
+// Compute the angle formed by two points of a PD
+double compute_angle(const PD & PersDiag, const int & i, const int & j){
+ std::pair<double,double> vect; double x1,y1, x2,y2;
+ x1 = PersDiag[i].first; y1 = PersDiag[i].second;
+ x2 = PersDiag[j].first; y2 = PersDiag[j].second;
+ if (y1 - y2 > 0){
+ vect.first = y1 - y2;
+ vect.second = x2 - x1;}
+ else{
+ if(y1 - y2 < 0){
+ vect.first = y2 - y1;
+ vect.second = x1 - x2;
+ }
+ else{
+ vect.first = 0;
+ vect.second = abs(x1 - x2);}
+ }
+ double norm = std::sqrt(vect.first*vect.first + vect.second*vect.second);
+ return asin(vect.second/norm);
+}
+
+// Compute the integral of |cos()| between alpha and beta, valid only if alpha is in [-pi,pi] and beta-alpha is in [0,pi]
+double compute_int_cos(const double & alpha, const double & beta){
+ double res = 0;
+ if (alpha >= 0 && alpha <= pi){
+ if (cos(alpha) >= 0){
+ if(pi/2 <= beta){res = 2-sin(alpha)-sin(beta);}
+ else{res = sin(beta)-sin(alpha);}
+ }
+ else{
+ if(1.5*pi <= beta){res = 2+sin(alpha)+sin(beta);}
+ else{res = sin(alpha)-sin(beta);}
+ }
+ }
+ if (alpha >= -pi && alpha <= 0){
+ if (cos(alpha) <= 0){
+ if(-pi/2 <= beta){res = 2+sin(alpha)+sin(beta);}
+ else{res = sin(alpha)-sin(beta);}
+ }
+ else{
+ if(pi/2 <= beta){res = 2-sin(alpha)-sin(beta);}
+ else{res = sin(beta)-sin(alpha);}
+ }
+ }
+ return res;
+}
+
+double compute_int(const double & theta1, const double & theta2, const int & p, const int & q, const PD & PD1, const PD & PD2){
+ double norm = std::sqrt( (PD1[p].first-PD2[q].first)*(PD1[p].first-PD2[q].first) + (PD1[p].second-PD2[q].second)*(PD1[p].second-PD2[q].second) );
+ double angle1;
+ if (PD1[p].first > PD2[q].first)
+ angle1 = theta1 - asin( (PD1[p].second-PD2[q].second)/norm );
+ else
+ angle1 = theta1 - asin( (PD2[q].second-PD1[p].second)/norm );
+ double angle2 = angle1 + theta2 - theta1;
+ double integral = compute_int_cos(angle1,angle2);
+ return norm*integral;
+}
+
+template<class Weight = std::function<double (std::pair<double,double>) > >
+std::vector<std::pair<double,double> > Fourier_feat(PD D, std::vector<std::pair<double,double> > Z, Weight weight = arctan_weight){
+ int m = D.size(); std::vector<std::pair<double,double> > B; int M = Z.size();
+ for(int i = 0; i < M; i++){
+ double d1 = 0; double d2 = 0; double zx = Z[i].first; double zy = Z[i].second;
+ for(int j = 0; j < m; j++){
+ double x = D[j].first; double y = D[j].second;
+ d1 += weight(D[j])*cos(x*zx + y*zy);
+ d2 += weight(D[j])*sin(x*zx + y*zy);
+ }
+ B.emplace_back(d1,d2);
+ }
+ return B;
+}
+
+std::vector<std::pair<double,double> > random_Fourier(double sigma, int M = 1000){
+ std::normal_distribution<double> distrib(0,1); std::vector<std::pair<double,double> > Z; std::random_device rd;
+ for(int i = 0; i < M; i++){
+ std::mt19937 e1(rd()); std::mt19937 e2(rd());
+ double zx = distrib(e1); double zy = distrib(e2);
+ Z.emplace_back(zx/sigma,zy/sigma);
+ }
+ return Z;
+}
+
+
+
+
+
+
+
+
+
+
+// ********************************************************************
+// Kernel computation.
+// ********************************************************************
+
+
+
+
+
+/** \brief Computes the Linear Persistence Weighted Gaussian Kernel between two persistence diagrams with random Fourier features.
+ * \ingroup kernel
+ *
+ * @param[in] PD1 first persistence diagram.
+ * @param[in] PD2 second persistence diagram.
+ * @param[in] sigma bandwidth parameter of the Gaussian Kernel used for the Kernel Mean Embedding of the diagrams.
+ * @param[in] weight weight function for the points in the diagrams.
+ * @param[in] M number of Fourier features (set -1 for exact computation).
+ *
+ */
+template<class Weight = std::function<double (std::pair<double,double>) > >
+double linear_persistence_weighted_gaussian_kernel(const PD & PD1, const PD & PD2, double sigma, Weight weight = arctan_weight, int M = 1000){
+
+ if(M == -1){
+ int num_pts1 = PD1.size(); int num_pts2 = PD2.size(); double k = 0;
+ for(int i = 0; i < num_pts1; i++)
+ for(int j = 0; j < num_pts2; j++)
+ k += weight(PD1[i])*weight(PD2[j])*exp(-((PD1[i].first-PD2[j].first)*(PD1[i].first-PD2[j].first) + (PD1[i].second-PD2[j].second)*(PD1[i].second-PD2[j].second))/(2*sigma*sigma));
+ return k;
+ }
+ else{
+ std::vector<std::pair<double,double> > Z = random_Fourier(sigma, M);
+ std::vector<std::pair<double,double> > B1 = Fourier_feat(PD1,Z,weight);
+ std::vector<std::pair<double,double> > B2 = Fourier_feat(PD2,Z,weight);
+ double d = 0; for(int i = 0; i < M; i++) d += B1[i].first*B2[i].first + B1[i].second*B2[i].second;
+ return d/M;
+ }
+}
+
+/** \brief Computes the Persistence Scale Space Kernel between two persistence diagrams with random Fourier features.
+ * \ingroup kernel
+ *
+ * @param[in] PD1 first persistence diagram.
+ * @param[in] PD2 second persistence diagram.
+ * @param[in] sigma bandwidth parameter of the Gaussian Kernel used for the Kernel Mean Embedding of the diagrams.
+ * @param[in] M number of Fourier features (set -1 for exact computation).
+ *
+ */
+double persistence_scale_space_kernel(const PD & PD1, const PD & PD2, double sigma, int M = 1000){
+ PD pd1 = PD1; int numpts = PD1.size(); for(int i = 0; i < numpts; i++) pd1.emplace_back(PD1[i].second,PD1[i].first);
+ PD pd2 = PD2; numpts = PD2.size(); for(int i = 0; i < numpts; i++) pd2.emplace_back(PD2[i].second,PD2[i].first);
+ return linear_persistence_weighted_gaussian_kernel(pd1, pd2, 2*sqrt(sigma), pss_weight, M) / (2*8*pi*sigma);
+}
+
+
+/** \brief Computes the Gaussian Persistence Weighted Gaussian Kernel between two persistence diagrams with random Fourier features.
+ * \ingroup kernel
+ *
+ * @param[in] PD1 first persistence diagram.
+ * @param[in] PD2 second persistence diagram.
+ * @param[in] sigma bandwidth parameter of the Gaussian Kernel used for the Kernel Mean Embedding of the diagrams.
+ * @param[in] tau bandwidth parameter of the Gaussian Kernel used between the embeddings.
+ * @param[in] weight weight function for the points in the diagrams.
+ * @param[in] M number of Fourier features (set -1 for exact computation).
+ *
+ */
+template<class Weight = std::function<double (std::pair<double,double>) > >
+double gaussian_persistence_weighted_gaussian_kernel(const PD & PD1, const PD & PD2, double sigma, double tau, Weight weight = arctan_weight, int M = 1000){
+ double k1 = linear_persistence_weighted_gaussian_kernel(PD1,PD1,sigma,weight,M);
+ double k2 = linear_persistence_weighted_gaussian_kernel(PD2,PD2,sigma,weight,M);
+ double k3 = linear_persistence_weighted_gaussian_kernel(PD1,PD2,sigma,weight,M);
+ return exp( - (k1+k2-2*k3) / (2*tau*tau) );
+}
+
+
+/** \brief Computes the Sliced Wasserstein Kernel between two persistence diagrams with sampled directions.
+ * \ingroup kernel
+ *
+ * @param[in] PD1 first persistence diagram.
+ * @param[in] PD2 second persistence diagram.
+ * @param[in] sigma bandwidth parameter.
+ * @param[in] N number of points sampled on the circle (set -1 for exact computation).
+ *
+ */
+double sliced_wasserstein_kernel(PD PD1, PD PD2, double sigma, int N = 100){
+
+ if(N == -1){
+
+ // Add projections onto diagonal.
+ int n1, n2; n1 = PD1.size(); n2 = PD2.size(); double max_ordinate = std::numeric_limits<double>::lowest();
+ for (int i = 0; i < n2; i++){
+ max_ordinate = std::max(max_ordinate, PD2[i].second);
+ PD1.emplace_back( (PD2[i].first+PD2[i].second)/2, (PD2[i].first+PD2[i].second)/2 );
+ }
+ for (int i = 0; i < n1; i++){
+ max_ordinate = std::max(max_ordinate, PD1[i].second);
+ PD2.emplace_back( (PD1[i].first+PD1[i].second)/2, (PD1[i].first+PD1[i].second)/2 );
+ }
+ int num_pts_dgm = PD1.size();
+
+ // Slightly perturb the points so that the PDs are in generic positions.
+ int mag = 0; while(max_ordinate > 10){mag++; max_ordinate/=10;}
+ double thresh = pow(10,-5+mag);
+ srand(time(NULL));
+ for (int i = 0; i < num_pts_dgm; i++){
+ PD1[i].first += thresh*(1.0-2.0*rand()/RAND_MAX); PD1[i].second += thresh*(1.0-2.0*rand()/RAND_MAX);
+ PD2[i].first += thresh*(1.0-2.0*rand()/RAND_MAX); PD2[i].second += thresh*(1.0-2.0*rand()/RAND_MAX);
+ }
+
+ // Compute all angles in both PDs.
+ std::vector<std::pair<double, std::pair<int,int> > > angles1, angles2;
+ for (int i = 0; i < num_pts_dgm; i++){
+ for (int j = i+1; j < num_pts_dgm; j++){
+ double theta1 = compute_angle(PD1,i,j); double theta2 = compute_angle(PD2,i,j);
+ angles1.emplace_back(theta1, std::pair<int,int>(i,j));
+ angles2.emplace_back(theta2, std::pair<int,int>(i,j));
+ }
+ }
+
+ // Sort angles.
+ std::sort(angles1.begin(), angles1.end(), sortAngle); std::sort(angles2.begin(), angles2.end(), sortAngle);
+
+ // Initialize orders of the points of both PDs (given by ordinates when theta = -pi/2).
+ std::vector<int> orderp1, orderp2;
+ for (int i = 0; i < num_pts_dgm; i++){ orderp1.push_back(i); orderp2.push_back(i); }
+ std::sort( orderp1.begin(), orderp1.end(), [=](int i, int j){ if(PD1[i].second != PD1[j].second) return (PD1[i].second < PD1[j].second); else return (PD1[i].first > PD1[j].first); } );
+ std::sort( orderp2.begin(), orderp2.end(), [=](int i, int j){ if(PD2[i].second != PD2[j].second) return (PD2[i].second < PD2[j].second); else return (PD2[i].first > PD2[j].first); } );
+
+ // Find the inverses of the orders.
+ std::vector<int> order1(num_pts_dgm); std::vector<int> order2(num_pts_dgm);
+ for(int i = 0; i < num_pts_dgm; i++) for (int j = 0; j < num_pts_dgm; j++) if(orderp1[j] == i){ order1[i] = j; break; }
+ for(int i = 0; i < num_pts_dgm; i++) for (int j = 0; j < num_pts_dgm; j++) if(orderp2[j] == i){ order2[i] = j; break; }
+
+ // Record all inversions of points in the orders as theta varies along the positive half-disk.
+ std::vector<std::vector<std::pair<int,double> > > anglePerm1(num_pts_dgm);
+ std::vector<std::vector<std::pair<int,double> > > anglePerm2(num_pts_dgm);
+
+ int M1 = angles1.size();
+ for (int i = 0; i < M1; i++){
+ double theta = angles1[i].first; int p = angles1[i].second.first; int q = angles1[i].second.second;
+ anglePerm1[order1[p]].emplace_back(p,theta);
+ anglePerm1[order1[q]].emplace_back(q,theta);
+ int a = order1[p]; int b = order1[q]; order1[p] = b; order1[q] = a;
+ }
+
+ int M2 = angles2.size();
+ for (int i = 0; i < M2; i++){
+ double theta = angles2[i].first; int p = angles2[i].second.first; int q = angles2[i].second.second;
+ anglePerm2[order2[p]].emplace_back(p,theta);
+ anglePerm2[order2[q]].emplace_back(q,theta);
+ int a = order2[p]; int b = order2[q]; order2[p] = b; order2[q] = a;
+ }
+
+ for (int i = 0; i < num_pts_dgm; i++){
+ anglePerm1[order1[i]].emplace_back(i,pi/2);
+ anglePerm2[order2[i]].emplace_back(i,pi/2);
+ }
+
+ // Compute the SW distance with the list of inversions.
+ double sw = 0;
+ for (int i = 0; i < num_pts_dgm; i++){
+ std::vector<std::pair<int,double> > U,V; U = anglePerm1[i]; V = anglePerm2[i];
+ double theta1, theta2; theta1 = -pi/2;
+ unsigned int ku, kv; ku = 0; kv = 0; theta2 = std::min(U[ku].second,V[kv].second);
+ while(theta1 != pi/2){
+ if(PD1[U[ku].first].first != PD2[V[kv].first].first || PD1[U[ku].first].second != PD2[V[kv].first].second)
+ if(theta1 != theta2)
+ sw += compute_int(theta1, theta2, U[ku].first, V[kv].first, PD1, PD2);
+ theta1 = theta2;
+ if ( (theta2 == U[ku].second) && ku < U.size()-1 ) ku++;
+ if ( (theta2 == V[kv].second) && kv < V.size()-1 ) kv++;
+ theta2 = std::min(U[ku].second, V[kv].second);
+ }
+ }
+
+ return exp( -(sw/pi)/(2*sigma*sigma) );
+
+ }
+
+
+ else{
+ double step = pi/N; double sw = 0;
+
+ // Add projections onto diagonal.
+ int n1, n2; n1 = PD1.size(); n2 = PD2.size();
+ for (int i = 0; i < n2; i++)
+ PD1.emplace_back( (PD2[i].first + PD2[i].second)/2, (PD2[i].first + PD2[i].second)/2 );
+ for (int i = 0; i < n1; i++)
+ PD2.emplace_back( (PD1[i].first + PD1[i].second)/2, (PD1[i].first + PD1[i].second)/2 );
+ int n = PD1.size();
+
+ // Sort and compare all projections.
+ //#pragma omp parallel for
+ for (int i = 0; i < N; i++){
+ std::vector<std::pair<int,double> > L1, L2;
+ for (int j = 0; j < n; j++){
+ L1.emplace_back( j, PD1[j].first*cos(-pi/2+i*step) + PD1[j].second*sin(-pi/2+i*step) );
+ L2.emplace_back( j, PD2[j].first*cos(-pi/2+i*step) + PD2[j].second*sin(-pi/2+i*step) );
+ }
+ std::sort(L1.begin(),L1.end(), myComp); std::sort(L2.begin(),L2.end(), myComp);
+ double f = 0; for (int j = 0; j < n; j++) f += std::abs(L1[j].second - L2[j].second);
+ sw += f*step;
+ }
+ return exp( -(sw/pi)/(2*sigma*sigma) );
+ }
+}
+
+
+} // namespace kernel
+
+} // namespace Gudhi
+
+#endif //KERNEL_H_
diff --git a/src/Kernels/test/CMakeLists.txt b/src/Kernels/test/CMakeLists.txt
new file mode 100644
index 00000000..95c72a7f
--- /dev/null
+++ b/src/Kernels/test/CMakeLists.txt
@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 2.6)
+project(kernel_tests)
+
+include(GUDHI_test_coverage)
+
+add_executable ( kernel_test_unit test_kernel.cpp )
+target_link_libraries(kernel_test_unit ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY})
+if (TBB_FOUND)
+ target_link_libraries(kernel_test_unit ${TBB_LIBRARIES})
+endif()
+
+gudhi_add_coverage_test(kernel_test_unit)
diff --git a/src/Kernels/test/test_kernel.cpp b/src/Kernels/test/test_kernel.cpp
new file mode 100644
index 00000000..db05fd28
--- /dev/null
+++ b/src/Kernels/test/test_kernel.cpp
@@ -0,0 +1,56 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Author(s): Mathieu Carrière
+ *
+ * Copyright (C) 2017 INRIA
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define BOOST_TEST_DYN_LINK
+#define BOOST_TEST_MODULE "kernel"
+
+#include <boost/test/unit_test.hpp>
+#include <cmath> // float comparison
+#include <limits>
+#include <string>
+#include <vector>
+#include <algorithm> // std::max
+#include <gudhi/kernel.h>
+#include <gudhi/distance_functions.h>
+#include <gudhi/reader_utils.h>
+
+BOOST_AUTO_TEST_CASE(check_PSS) {
+ std::vector< std::pair<double, double> > v1, v2;
+ v1.emplace_back(std::pair<double,double>(0,1));
+ v2.emplace_back(std::pair<double,double>(0,2));
+ BOOST_CHECK(std::abs(Gudhi::kernel::pssk(v1,v2,1) - Gudhi::kernel::approx_pssk(v1,v2,1)) <= 1e-1);
+}
+
+BOOST_AUTO_TEST_CASE(check_PWG) {
+ std::vector< std::pair<double, double> > v1, v2;
+ v1.emplace_back(std::pair<double,double>(0,1));
+ v2.emplace_back(std::pair<double,double>(0,2));
+ BOOST_CHECK(std::abs(Gudhi::kernel::lpwgk(v1,v2,1) - Gudhi::kernel::approx_lpwgk(v1,v2,1)) <= 1e-1);
+ BOOST_CHECK(std::abs(Gudhi::kernel::gpwgk(v1,v2,1,1) - Gudhi::kernel::approx_gpwgk(v1,v2,1,1)) <= 1e-1);
+}
+
+BOOST_AUTO_TEST_CASE(check_SW) {
+ std::vector< std::pair<double, double> > v1, v2;
+ v2.emplace_back(std::pair<double,double>(0,2));
+ BOOST_CHECK(std::abs(Gudhi::kernel::sw(v1,v2) - Gudhi::kernel::approx_sw(v1,v2)) <= 1e-3);
+ BOOST_CHECK(std::abs(Gudhi::kernel::sw(v1,v2) - 2*std::sqrt(2)/3.1415) <= 1e-3);
+}
diff --git a/src/Persistence_representations/example/persistence_weighted_gaussian.cpp b/src/Persistence_representations/example/persistence_weighted_gaussian.cpp
new file mode 100644
index 00000000..e95b9445
--- /dev/null
+++ b/src/Persistence_representations/example/persistence_weighted_gaussian.cpp
@@ -0,0 +1,96 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Author(s): Mathieu Carriere
+ *
+ * Copyright (C) 2018 INRIA (France)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gudhi/Persistence_weighted_gaussian.h>
+
+#include <iostream>
+#include <vector>
+#include <utility>
+
+using PD = std::vector<std::pair<double,double> >;
+using PWG = Gudhi::Persistence_representations::Persistence_weighted_gaussian;
+
+int main(int argc, char** argv) {
+
+ std::vector<std::pair<double, double> > persistence1;
+ std::vector<std::pair<double, double> > persistence2;
+
+ persistence1.push_back(std::make_pair(1, 2));
+ persistence1.push_back(std::make_pair(6, 8));
+ persistence1.push_back(std::make_pair(0, 4));
+ persistence1.push_back(std::make_pair(3, 8));
+
+ persistence2.push_back(std::make_pair(2, 9));
+ persistence2.push_back(std::make_pair(1, 6));
+ persistence2.push_back(std::make_pair(3, 5));
+ persistence2.push_back(std::make_pair(6, 10));
+
+ PWG PWG1(persistence1);
+ PWG PWG2(persistence2);
+ double sigma = 1;
+ double tau = 1;
+ int m = 1000;
+
+
+
+ // Linear PWG
+
+ std::cout << PWG1.compute_scalar_product (PWG2, sigma, PWG::arctan_weight, m) << std::endl;
+ std::cout << PWG1.compute_scalar_product (PWG2, sigma, PWG::arctan_weight, -1) << std::endl;
+
+ std::cout << PWG1.distance (PWG2, sigma, PWG::arctan_weight, m) << std::endl;
+ std::cout << PWG1.distance (PWG2, sigma, PWG::arctan_weight, -1) << std::endl;
+
+
+
+
+
+
+
+ // Gaussian PWG
+
+ std::cout << std::exp( -PWG1.distance (PWG2, sigma, PWG::arctan_weight, m, 2) ) / (2*tau*tau) << std::endl;
+ std::cout << std::exp( -PWG1.distance (PWG2, sigma, PWG::arctan_weight, -1, 2) ) / (2*tau*tau) << std::endl;
+
+
+
+
+
+
+
+ // PSS
+
+ PD pd1 = persistence1; int numpts = persistence1.size(); for(int i = 0; i < numpts; i++) pd1.emplace_back(persistence1[i].second,persistence1[i].first);
+ PD pd2 = persistence2; numpts = persistence2.size(); for(int i = 0; i < numpts; i++) pd2.emplace_back(persistence2[i].second,persistence2[i].first);
+
+ PWG pwg1(pd1);
+ PWG pwg2(pd2);
+
+ std::cout << pwg1.compute_scalar_product (pwg2, 2*std::sqrt(sigma), PWG::pss_weight, m) / (16*pi*sigma) << std::endl;
+ std::cout << pwg1.compute_scalar_product (pwg2, 2*std::sqrt(sigma), PWG::pss_weight, -1) / (16*pi*sigma) << std::endl;
+
+ std::cout << pwg1.distance (pwg2, 2*std::sqrt(sigma), PWG::pss_weight, m) / (16*pi*sigma) << std::endl;
+ std::cout << pwg1.distance (pwg2, 2*std::sqrt(sigma), PWG::pss_weight, -1) / (16*pi*sigma) << std::endl;
+
+
+ return 0;
+}
diff --git a/src/Persistence_representations/example/sliced_wasserstein.cpp b/src/Persistence_representations/example/sliced_wasserstein.cpp
new file mode 100644
index 00000000..673d8474
--- /dev/null
+++ b/src/Persistence_representations/example/sliced_wasserstein.cpp
@@ -0,0 +1,55 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Author(s): Mathieu Carriere
+ *
+ * Copyright (C) 2018 INRIA (France)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gudhi/Sliced_Wasserstein.h>
+
+#include <iostream>
+#include <vector>
+#include <utility>
+
+using SW = Gudhi::Persistence_representations::Sliced_Wasserstein;
+
+int main(int argc, char** argv) {
+
+ std::vector<std::pair<double, double> > persistence1;
+ std::vector<std::pair<double, double> > persistence2;
+
+ persistence1.push_back(std::make_pair(1, 2));
+ persistence1.push_back(std::make_pair(6, 8));
+ persistence1.push_back(std::make_pair(0, 4));
+ persistence1.push_back(std::make_pair(3, 8));
+
+ persistence2.push_back(std::make_pair(2, 9));
+ persistence2.push_back(std::make_pair(1, 6));
+ persistence2.push_back(std::make_pair(3, 5));
+ persistence2.push_back(std::make_pair(6, 10));
+
+ SW SW1(persistence1);
+ SW SW2(persistence2);
+
+ std::cout << SW1.compute_sliced_wasserstein_distance(SW2,100) << std::endl;
+ std::cout << SW1.compute_sliced_wasserstein_distance(SW2,-1) << std::endl;
+ std::cout << SW1.compute_scalar_product(SW2,1,100) << std::endl;
+ std::cout << SW1.distance(SW2,1,100,1) << std::endl;
+
+ return 0;
+}
diff --git a/src/Persistence_representations/include/gudhi/Persistence_weighted_gaussian.h b/src/Persistence_representations/include/gudhi/Persistence_weighted_gaussian.h
new file mode 100644
index 00000000..2884885c
--- /dev/null
+++ b/src/Persistence_representations/include/gudhi/Persistence_weighted_gaussian.h
@@ -0,0 +1,143 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Author(s): Mathieu Carriere
+ *
+ * Copyright (C) 2018 INRIA (France)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef PERSISTENCE_WEIGHTED_GAUSSIAN_H_
+#define PERSISTENCE_WEIGHTED_GAUSSIAN_H_
+
+#ifdef GUDHI_USE_TBB
+#include <tbb/parallel_for.h>
+#endif
+
+// gudhi include
+#include <gudhi/read_persistence_from_file.h>
+
+// standard include
+#include <cmath>
+#include <iostream>
+#include <vector>
+#include <limits>
+#include <fstream>
+#include <sstream>
+#include <algorithm>
+#include <string>
+#include <utility>
+#include <functional>
+#include <boost/math/constants/constants.hpp>
+
+double pi = boost::math::constants::pi<double>();
+using PD = std::vector<std::pair<double,double> >;
+
+namespace Gudhi {
+namespace Persistence_representations {
+
+class Persistence_weighted_gaussian{
+
+ protected:
+ PD diagram;
+
+ public:
+
+ Persistence_weighted_gaussian(PD _diagram){diagram = _diagram;}
+ PD get_diagram(){return this->diagram;}
+
+
+ // **********************************
+ // Utils.
+ // **********************************
+
+
+ static double pss_weight(std::pair<double,double> P){
+ if(P.second > P.first) return 1;
+ else return -1;
+ }
+
+ static double arctan_weight(std::pair<double,double> P){
+ return atan(P.second - P.first);
+ }
+
+ template<class Weight = std::function<double (std::pair<double,double>) > >
+ std::vector<std::pair<double,double> > Fourier_feat(PD D, std::vector<std::pair<double,double> > Z, Weight weight = arctan_weight){
+ int m = D.size(); std::vector<std::pair<double,double> > B; int M = Z.size();
+ for(int i = 0; i < M; i++){
+ double d1 = 0; double d2 = 0; double zx = Z[i].first; double zy = Z[i].second;
+ for(int j = 0; j < m; j++){
+ double x = D[j].first; double y = D[j].second;
+ d1 += weight(D[j])*cos(x*zx + y*zy);
+ d2 += weight(D[j])*sin(x*zx + y*zy);
+ }
+ B.emplace_back(d1,d2);
+ }
+ return B;
+ }
+
+ std::vector<std::pair<double,double> > random_Fourier(double sigma, int M = 1000){
+ std::normal_distribution<double> distrib(0,1); std::vector<std::pair<double,double> > Z; std::random_device rd;
+ for(int i = 0; i < M; i++){
+ std::mt19937 e1(rd()); std::mt19937 e2(rd());
+ double zx = distrib(e1); double zy = distrib(e2);
+ Z.emplace_back(zx/sigma,zy/sigma);
+ }
+ return Z;
+ }
+
+
+
+ // **********************************
+ // Scalar product + distance.
+ // **********************************
+
+
+ template<class Weight = std::function<double (std::pair<double,double>) > >
+ double compute_scalar_product(Persistence_weighted_gaussian second, double sigma, Weight weight = arctan_weight, int m = 1000){
+
+ PD diagram1 = this->diagram; PD diagram2 = second.diagram;
+
+ if(m == -1){
+ int num_pts1 = diagram1.size(); int num_pts2 = diagram2.size(); double k = 0;
+ for(int i = 0; i < num_pts1; i++)
+ for(int j = 0; j < num_pts2; j++)
+ k += weight(diagram1[i])*weight(diagram2[j])*exp(-((diagram1[i].first - diagram2[j].first) * (diagram1[i].first - diagram2[j].first) +
+ (diagram1[i].second - diagram2[j].second) * (diagram1[i].second - diagram2[j].second))
+ /(2*sigma*sigma));
+ return k;
+ }
+ else{
+ std::vector<std::pair<double,double> > z = random_Fourier(sigma, m);
+ std::vector<std::pair<double,double> > b1 = Fourier_feat(diagram1,z,weight);
+ std::vector<std::pair<double,double> > b2 = Fourier_feat(diagram2,z,weight);
+ double d = 0; for(int i = 0; i < m; i++) d += b1[i].first*b2[i].first + b1[i].second*b2[i].second;
+ return d/m;
+ }
+ }
+
+ template<class Weight = std::function<double (std::pair<double,double>) > >
+ double distance(Persistence_weighted_gaussian second, double sigma, Weight weight = arctan_weight, int m = 1000, double power = 1) {
+ return std::pow(this->compute_scalar_product(*this, sigma, weight, m) + second.compute_scalar_product(second, sigma, weight, m)-2*this->compute_scalar_product(second, sigma, weight, m), power/2.0);
+ }
+
+
+};
+
+} // namespace Persistence_weighted_gaussian
+} // namespace Gudhi
+
+#endif // PERSISTENCE_WEIGHTED_GAUSSIAN_H_
diff --git a/src/Persistence_representations/include/gudhi/Sliced_Wasserstein.h b/src/Persistence_representations/include/gudhi/Sliced_Wasserstein.h
new file mode 100644
index 00000000..4fa6151f
--- /dev/null
+++ b/src/Persistence_representations/include/gudhi/Sliced_Wasserstein.h
@@ -0,0 +1,285 @@
+/* This file is part of the Gudhi Library. The Gudhi library
+ * (Geometric Understanding in Higher Dimensions) is a generic C++
+ * library for computational topology.
+ *
+ * Author(s): Mathieu Carriere
+ *
+ * Copyright (C) 2018 INRIA (France)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SLICED_WASSERSTEIN_H_
+#define SLICED_WASSERSTEIN_H_
+
+#ifdef GUDHI_USE_TBB
+#include <tbb/parallel_for.h>
+#endif
+
+// gudhi include
+#include <gudhi/read_persistence_from_file.h>
+
+// standard include
+#include <cmath>
+#include <iostream>
+#include <vector>
+#include <limits>
+#include <fstream>
+#include <sstream>
+#include <algorithm>
+#include <string>
+#include <utility>
+#include <functional>
+#include <boost/math/constants/constants.hpp>
+
+double pi = boost::math::constants::pi<double>();
+using PD = std::vector<std::pair<double,double> >;
+
+namespace Gudhi {
+namespace Persistence_representations {
+
+class Sliced_Wasserstein {
+
+ protected:
+ PD diagram;
+
+ public:
+
+ Sliced_Wasserstein(PD _diagram){diagram = _diagram;}
+ PD get_diagram(){return this->diagram;}
+
+
+ // **********************************
+ // Utils.
+ // **********************************
+
+ // Compute the angle formed by two points of a PD
+ double compute_angle(PD diag, int i, int j){
+ std::pair<double,double> vect; double x1,y1, x2,y2;
+ x1 = diag[i].first; y1 = diag[i].second;
+ x2 = diag[j].first; y2 = diag[j].second;
+ if (y1 - y2 > 0){
+ vect.first = y1 - y2;
+ vect.second = x2 - x1;}
+ else{
+ if(y1 - y2 < 0){
+ vect.first = y2 - y1;
+ vect.second = x1 - x2;
+ }
+ else{
+ vect.first = 0;
+ vect.second = abs(x1 - x2);}
+ }
+ double norm = std::sqrt(vect.first*vect.first + vect.second*vect.second);
+ return asin(vect.second/norm);
+ }
+
+ // Compute the integral of |cos()| between alpha and beta, valid only if alpha is in [-pi,pi] and beta-alpha is in [0,pi]
+ double compute_int_cos(const double & alpha, const double & beta){
+ double res = 0;
+ if (alpha >= 0 && alpha <= pi){
+ if (cos(alpha) >= 0){
+ if(pi/2 <= beta){res = 2-sin(alpha)-sin(beta);}
+ else{res = sin(beta)-sin(alpha);}
+ }
+ else{
+ if(1.5*pi <= beta){res = 2+sin(alpha)+sin(beta);}
+ else{res = sin(alpha)-sin(beta);}
+ }
+ }
+ if (alpha >= -pi && alpha <= 0){
+ if (cos(alpha) <= 0){
+ if(-pi/2 <= beta){res = 2+sin(alpha)+sin(beta);}
+ else{res = sin(alpha)-sin(beta);}
+ }
+ else{
+ if(pi/2 <= beta){res = 2-sin(alpha)-sin(beta);}
+ else{res = sin(beta)-sin(alpha);}
+ }
+ }
+ return res;
+ }
+
+ double compute_int(const double & theta1, const double & theta2, const int & p, const int & q, const PD & PD1, const PD & PD2){
+ double norm = std::sqrt( (PD1[p].first-PD2[q].first)*(PD1[p].first-PD2[q].first) + (PD1[p].second-PD2[q].second)*(PD1[p].second-PD2[q].second) );
+ double angle1;
+ if (PD1[p].first > PD2[q].first)
+ angle1 = theta1 - asin( (PD1[p].second-PD2[q].second)/norm );
+ else
+ angle1 = theta1 - asin( (PD2[q].second-PD1[p].second)/norm );
+ double angle2 = angle1 + theta2 - theta1;
+ double integral = compute_int_cos(angle1,angle2);
+ return norm*integral;
+ }
+
+
+
+
+ // **********************************
+ // Scalar product + distance.
+ // **********************************
+
+ double compute_sliced_wasserstein_distance(Sliced_Wasserstein second, int approx) {
+
+ PD diagram1 = this->diagram; PD diagram2 = second.diagram; double sw = 0;
+
+ if(approx == -1){
+
+ // Add projections onto diagonal.
+ int n1, n2; n1 = diagram1.size(); n2 = diagram2.size(); double max_ordinate = std::numeric_limits<double>::lowest();
+ for (int i = 0; i < n2; i++){
+ max_ordinate = std::max(max_ordinate, diagram2[i].second);
+ diagram1.emplace_back( (diagram2[i].first+diagram2[i].second)/2, (diagram2[i].first+diagram2[i].second)/2 );
+ }
+ for (int i = 0; i < n1; i++){
+ max_ordinate = std::max(max_ordinate, diagram1[i].second);
+ diagram2.emplace_back( (diagram1[i].first+diagram1[i].second)/2, (diagram1[i].first+diagram1[i].second)/2 );
+ }
+ int num_pts_dgm = diagram1.size();
+
+ // Slightly perturb the points so that the PDs are in generic positions.
+ int mag = 0; while(max_ordinate > 10){mag++; max_ordinate/=10;}
+ double thresh = pow(10,-5+mag);
+ srand(time(NULL));
+ for (int i = 0; i < num_pts_dgm; i++){
+ diagram1[i].first += thresh*(1.0-2.0*rand()/RAND_MAX); diagram1[i].second += thresh*(1.0-2.0*rand()/RAND_MAX);
+ diagram2[i].first += thresh*(1.0-2.0*rand()/RAND_MAX); diagram2[i].second += thresh*(1.0-2.0*rand()/RAND_MAX);
+ }
+
+ // Compute all angles in both PDs.
+ std::vector<std::pair<double, std::pair<int,int> > > angles1, angles2;
+ for (int i = 0; i < num_pts_dgm; i++){
+ for (int j = i+1; j < num_pts_dgm; j++){
+ double theta1 = compute_angle(diagram1,i,j); double theta2 = compute_angle(diagram2,i,j);
+ angles1.emplace_back(theta1, std::pair<int,int>(i,j));
+ angles2.emplace_back(theta2, std::pair<int,int>(i,j));
+ }
+ }
+
+ // Sort angles.
+ std::sort(angles1.begin(), angles1.end(), [=](std::pair<double, std::pair<int,int> >& p1, const std::pair<double, std::pair<int,int> >& p2){return (p1.first < p2.first);});
+ std::sort(angles2.begin(), angles2.end(), [=](std::pair<double, std::pair<int,int> >& p1, const std::pair<double, std::pair<int,int> >& p2){return (p1.first < p2.first);});
+
+ // Initialize orders of the points of both PDs (given by ordinates when theta = -pi/2).
+ std::vector<int> orderp1, orderp2;
+ for (int i = 0; i < num_pts_dgm; i++){ orderp1.push_back(i); orderp2.push_back(i); }
+ std::sort( orderp1.begin(), orderp1.end(), [=](int i, int j){ if(diagram1[i].second != diagram1[j].second) return (diagram1[i].second < diagram1[j].second); else return (diagram1[i].first > diagram1[j].first); } );
+ std::sort( orderp2.begin(), orderp2.end(), [=](int i, int j){ if(diagram2[i].second != diagram2[j].second) return (diagram2[i].second < diagram2[j].second); else return (diagram2[i].first > diagram2[j].first); } );
+
+ // Find the inverses of the orders.
+ std::vector<int> order1(num_pts_dgm); std::vector<int> order2(num_pts_dgm);
+ for(int i = 0; i < num_pts_dgm; i++) for (int j = 0; j < num_pts_dgm; j++) if(orderp1[j] == i){ order1[i] = j; break; }
+ for(int i = 0; i < num_pts_dgm; i++) for (int j = 0; j < num_pts_dgm; j++) if(orderp2[j] == i){ order2[i] = j; break; }
+
+ // Record all inversions of points in the orders as theta varies along the positive half-disk.
+ std::vector<std::vector<std::pair<int,double> > > anglePerm1(num_pts_dgm);
+ std::vector<std::vector<std::pair<int,double> > > anglePerm2(num_pts_dgm);
+
+ int m1 = angles1.size();
+ for (int i = 0; i < m1; i++){
+ double theta = angles1[i].first; int p = angles1[i].second.first; int q = angles1[i].second.second;
+ anglePerm1[order1[p]].emplace_back(p,theta);
+ anglePerm1[order1[q]].emplace_back(q,theta);
+ int a = order1[p]; int b = order1[q]; order1[p] = b; order1[q] = a;
+ }
+
+ int m2 = angles2.size();
+ for (int i = 0; i < m2; i++){
+ double theta = angles2[i].first; int p = angles2[i].second.first; int q = angles2[i].second.second;
+ anglePerm2[order2[p]].emplace_back(p,theta);
+ anglePerm2[order2[q]].emplace_back(q,theta);
+ int a = order2[p]; int b = order2[q]; order2[p] = b; order2[q] = a;
+ }
+
+ for (int i = 0; i < num_pts_dgm; i++){
+ anglePerm1[order1[i]].emplace_back(i,pi/2);
+ anglePerm2[order2[i]].emplace_back(i,pi/2);
+ }
+
+ // Compute the SW distance with the list of inversions.
+ for (int i = 0; i < num_pts_dgm; i++){
+ std::vector<std::pair<int,double> > u,v; u = anglePerm1[i]; v = anglePerm2[i];
+ double theta1, theta2; theta1 = -pi/2;
+ unsigned int ku, kv; ku = 0; kv = 0; theta2 = std::min(u[ku].second,v[kv].second);
+ while(theta1 != pi/2){
+ if(diagram1[u[ku].first].first != diagram2[v[kv].first].first || diagram1[u[ku].first].second != diagram2[v[kv].first].second)
+ if(theta1 != theta2)
+ sw += compute_int(theta1, theta2, u[ku].first, v[kv].first, diagram1, diagram2);
+ theta1 = theta2;
+ if ( (theta2 == u[ku].second) && ku < u.size()-1 ) ku++;
+ if ( (theta2 == v[kv].second) && kv < v.size()-1 ) kv++;
+ theta2 = std::min(u[ku].second, v[kv].second);
+ }
+ }
+ }
+
+
+ else{
+ double step = pi/approx;
+
+ // Add projections onto diagonal.
+ int n1, n2; n1 = diagram1.size(); n2 = diagram2.size();
+ for (int i = 0; i < n2; i++)
+ diagram1.emplace_back( (diagram2[i].first + diagram2[i].second)/2, (diagram2[i].first + diagram2[i].second)/2 );
+ for (int i = 0; i < n1; i++)
+ diagram2.emplace_back( (diagram1[i].first + diagram1[i].second)/2, (diagram1[i].first + diagram1[i].second)/2 );
+ int n = diagram1.size();
+
+ // Sort and compare all projections.
+ #ifdef GUDHI_USE_TBB
+ tbb::parallel_for(0, approx, [&](int i){
+ std::vector<std::pair<int,double> > l1, l2;
+ for (int j = 0; j < n; j++){
+ l1.emplace_back( j, diagram1[j].first*cos(-pi/2+i*step) + diagram1[j].second*sin(-pi/2+i*step) );
+ l2.emplace_back( j, diagram2[j].first*cos(-pi/2+i*step) + diagram2[j].second*sin(-pi/2+i*step) );
+ }
+ std::sort(l1.begin(),l1.end(), [=](const std::pair<int,double> & p1, const std::pair<int,double> & p2){return p1.second < p2.second;});
+ std::sort(l2.begin(),l2.end(), [=](const std::pair<int,double> & p1, const std::pair<int,double> & p2){return p1.second < p2.second;});
+ double f = 0; for (int j = 0; j < n; j++) f += std::abs(l1[j].second - l2[j].second);
+ sw += f*step;
+ });
+ #else
+ for (int i = 0; i < approx; i++){
+ std::vector<std::pair<int,double> > l1, l2;
+ for (int j = 0; j < n; j++){
+ l1.emplace_back( j, diagram1[j].first*cos(-pi/2+i*step) + diagram1[j].second*sin(-pi/2+i*step) );
+ l2.emplace_back( j, diagram2[j].first*cos(-pi/2+i*step) + diagram2[j].second*sin(-pi/2+i*step) );
+ }
+ std::sort(l1.begin(),l1.end(), [=](const std::pair<int,double> & p1, const std::pair<int,double> & p2){return p1.second < p2.second;});
+ std::sort(l2.begin(),l2.end(), [=](const std::pair<int,double> & p1, const std::pair<int,double> & p2){return p1.second < p2.second;});
+ double f = 0; for (int j = 0; j < n; j++) f += std::abs(l1[j].second - l2[j].second);
+ sw += f*step;
+ }
+ #endif
+ }
+
+ return sw/pi;
+ }
+
+
+ double compute_scalar_product(Sliced_Wasserstein second, double sigma, int approx = 100) {
+ return std::exp(-compute_sliced_wasserstein_distance(second, approx)/(2*sigma*sigma));
+ }
+
+ double distance(Sliced_Wasserstein second, double sigma, int approx = 100, double power = 1) {
+ return std::pow(this->compute_scalar_product(*this, sigma, approx) + second.compute_scalar_product(second, sigma, approx)-2*this->compute_scalar_product(second, sigma, approx), power/2.0);
+ }
+
+
+};
+
+} // namespace Sliced_Wasserstein
+} // namespace Gudhi
+
+#endif // SLICED_WASSERSTEIN_H_
diff --git a/src/cmake/modules/GUDHI_modules.cmake b/src/cmake/modules/GUDHI_modules.cmake
index f95d0c34..205ee8a1 100644
--- a/src/cmake/modules/GUDHI_modules.cmake
+++ b/src/cmake/modules/GUDHI_modules.cmake
@@ -16,8 +16,8 @@ function(add_gudhi_module file_path)
endfunction(add_gudhi_module)
-option(WITH_GUDHI_BENCHMARK "Activate/desactivate benchmark compilation" OFF)
-option(WITH_GUDHI_EXAMPLE "Activate/desactivate examples compilation and installation" OFF)
+option(WITH_GUDHI_BENCHMARK "Activate/desactivate benchmark compilation" ON)
+option(WITH_GUDHI_EXAMPLE "Activate/desactivate examples compilation and installation" ON)
option(WITH_GUDHI_PYTHON "Activate/desactivate python module compilation and installation" ON)
option(WITH_GUDHI_TEST "Activate/desactivate examples compilation and installation" ON)
option(WITH_GUDHI_UTILITIES "Activate/desactivate utilities compilation and installation" ON)