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Diffstat (limited to 'src/Persistence_representations/example/persistence_heat_maps.cpp')
-rw-r--r-- | src/Persistence_representations/example/persistence_heat_maps.cpp | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/src/Persistence_representations/example/persistence_heat_maps.cpp b/src/Persistence_representations/example/persistence_heat_maps.cpp new file mode 100644 index 00000000..1bf3a637 --- /dev/null +++ b/src/Persistence_representations/example/persistence_heat_maps.cpp @@ -0,0 +1,89 @@ +/* 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): Pawel Dlotko and Mathieu Carriere + * + * Copyright (C) 2019 Inria + * + * Modifications: + * - 2018/04 MC: Add persistence heat maps computation + * + * Modification(s): + * - YYYY/MM Author: Description of the modification + */ + +#include <gudhi/Persistence_heat_maps.h> +#include <gudhi/common_persistence_representations.h> + +#include <iostream> +#include <vector> +#include <utility> +#include <functional> +#include <cmath> + +std::function<double(std::pair<double, double>, std::pair<double, double>)> Gaussian_function(double sigma) { + return [=](std::pair<double, double> p, std::pair<double, double> q) { + return std::exp(-((p.first - q.first) * (p.first - q.first) + (p.second - q.second) * (p.second - q.second)) / + (sigma)); + }; +} + +using constant_scaling_function = Gudhi::Persistence_representations::constant_scaling_function; +using Persistence_heat_maps = Gudhi::Persistence_representations::Persistence_heat_maps<constant_scaling_function>; + +int main(int argc, char** argv) { + // create two simple vectors with birth--death pairs: + + 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)); + + // over here we define a function we sill put on a top on every birth--death pair in the persistence interval. It can + // be anything. Over here we will use standard Gaussian + std::vector<std::vector<double> > filter = Gudhi::Persistence_representations::create_Gaussian_filter(5, 1); + + // creating two heat maps. + Persistence_heat_maps hm1(persistence1, filter, false, 20, 0, 11); + Persistence_heat_maps hm2(persistence2, filter, false, 20, 0, 11); + + std::vector<Persistence_heat_maps*> vector_of_maps; + vector_of_maps.push_back(&hm1); + vector_of_maps.push_back(&hm2); + + // compute median/mean of a vector of heat maps: + Persistence_heat_maps mean; + mean.compute_mean(vector_of_maps); + Persistence_heat_maps median; + median.compute_median(vector_of_maps); + + // to compute L^1 distance between hm1 and hm2: + std::cout << "The L^1 distance is : " << hm1.distance(hm2, 1) << std::endl; + + // to average of hm1 and hm2: + std::vector<Persistence_heat_maps*> to_average; + to_average.push_back(&hm1); + to_average.push_back(&hm2); + Persistence_heat_maps av; + av.compute_average(to_average); + + // to compute scalar product of hm1 and hm2: + std::cout << "Scalar product is : " << hm1.compute_scalar_product(hm2) << std::endl; + + Persistence_heat_maps hm1k(persistence1, Gaussian_function(1.0)); + Persistence_heat_maps hm2k(persistence2, Gaussian_function(1.0)); + Persistence_heat_maps hm1i(persistence1, Gaussian_function(1.0), 20, 20, 0, 11, 0, 11); + Persistence_heat_maps hm2i(persistence2, Gaussian_function(1.0), 20, 20, 0, 11, 0, 11); + std::cout << "Scalar product computed with exact 2D kernel on grid is : " << hm1i.compute_scalar_product(hm2i) + << std::endl; + std::cout << "Scalar product computed with exact 2D kernel is : " << hm1k.compute_scalar_product(hm2k) << std::endl; + + return 0; +} |