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65 lines
2.3 KiB
65 lines
2.3 KiB
#include <medusa/Medusa.hpp>
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#include <medusa/bits/domains/GeneralFill.hpp>
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using namespace mm; // NOLINT
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using namespace std; // NOLINT
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using namespace Eigen; // NOLINT
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/// Definition of custom stencil selection algorithms.
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/// http://e6.ijs.si/medusa/wiki/index.php/Customization
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/// A bad (inefficient and not robust) visibility based stencil finder.
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struct VisibilityStencil {
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int num_closest;
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explicit VisibilityStencil(int num_closest) : num_closest(num_closest) {}
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/// Check for straight-line visibility by testing intermediate points with some density.
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template <typename vec_t>
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bool visible(const vec_t& p, const vec_t& q, const DomainDiscretization<vec_t>& domain) const {
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int density = 100;
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vec_t increment = (q-p) / density;
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for (int i = 1; i < density; ++i) {
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if (!domain.contains(p + i*increment)) {
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return false;
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}
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}
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return true;
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}
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/// Method responsible for stencil construction.
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template <typename vec_t>
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void operator()(DomainDiscretization<vec_t>& domain) const {
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int N = domain.size();
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KDTree<vec_t> tree(domain.positions());
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for (int i = 0; i < N; ++i) {
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Range<int> indices = tree.query(domain.pos(i), num_closest).first;
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for (int j : indices) {
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if (visible(domain.pos(i), domain.pos(j), domain)) {
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domain.support(i).push_back(j);
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}
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}
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}
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}
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};
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int main() {
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PolygonShape<Vec2d> poly({{0.5, 0.0}, {1.5, 0.0}, {1.5, 0.6}, {1.1, 0.6}, {1.0, 0.2},
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{0.9, 0.6}, {0.5, 0.6}});
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GeneralFill<Vec2d> fill; fill.seed(0);
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DomainDiscretization<Vec2d> domain = poly.discretizeWithDensity(
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[](const Vec2d&) { return 0.05; }, fill);
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DomainDiscretization<Vec2d> domain_copy = domain;
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int n = 25;
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domain.findSupport(VisibilityStencil(n));
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domain_copy.findSupport(FindClosest(n));
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std::ofstream out_file("custom_stencils_visibility_data.m");
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out_file << "positions = " << domain.positions() << ";" << std::endl;
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out_file << "stencils_closest = " << domain_copy.supports() << ";" << std::endl;
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out_file << "stencils_visibility = " << pad(domain.supports(), -1) << ";" << std::endl;
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return 0;
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}
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