New Gaussian Accelerated Billiard Walk

.gitignore

@@ -9,3 +9,4 @@ test/Testing/Temporary/CTestCostData.txt
 build/
 .vscode
 .DS_Store
+test/.cache

examples/crhmc_sampling/.gitignore

@@ -5,3 +5,4 @@ CRHMC_SIMD_*
 sampling_functions
 simple_crhmc
 libQD_LIB.a
+liblp_solve.a

include/convex_bodies/hpolytope.h

@@ -541,7 +541,6 @@ class HPolytope {
 
         NT lamda = 0;
         VT sum_nom;
-        unsigned int j;
         int m = num_of_hyperplanes(), facet;
 
         Ar.noalias() += lambda_prev*Av;
@@ -909,6 +908,19 @@ class HPolytope {
             v += a;
     }
 
+    template <typename update_parameters>
+    NT compute_reflection(Point &v, const Point &, MT const &AE, VT const &AEA, NT const &vEv, update_parameters const &params) const {
+
+            Point a((-2.0 * params.inner_vi_ak) * A.row(params.facet_prev));
+            VT x = v.getCoefficients();
+            NT new_vEv = vEv - (4.0 * params.inner_vi_ak) * (AE.row(params.facet_prev).dot(x))
+                       + (4.0 * params.inner_vi_ak * params.inner_vi_ak) * AEA(params.facet_prev);
+            v += a;
+            NT coeff = std::sqrt(vEv / new_vEv);
+            v = v * coeff;
+            return coeff;
+    }
+
     void update_position_internal(NT&){}
 
     template <class bfunc, class NonLinearOracle>

include/convex_bodies/orderpolytope.h

@@ -94,6 +94,12 @@ class OrderPolytope {
         return _A.sparseView();
     }
 
+    // return the matrix A
+    MT get_full_mat() const
+    {
+        return _A;
+    }
+
 
     VT get_vec() const
     {

include/generators/order_polytope_generator.h

@@ -9,11 +9,25 @@
 #ifndef ORDER_POLYTOPES_GEN_H
 #define ORDER_POLYTOPES_GEN_H
 
+#include <chrono>
 #include <sstream>
+#include <type_traits>
 #include <unordered_map>
-#include "misc.h"
+#include <vector>
+#include <algorithm>
+
+#include "misc/misc.h"
 #include "misc/poset.h"
 
+#include <boost/random.hpp>
+#include <boost/random/uniform_int.hpp>
+#include <boost/random/normal_distribution.hpp>
+#include <boost/random/uniform_real_distribution.hpp>
+
+#include "generators/boost_random_number_generator.hpp"
+
+#include "convex_bodies/orderpolytope.h"
+
 
 // Instances taken from: https://github.com/ttalvitie/le-counting-practice
 static const std::unordered_map<std::string, std::string> instances =
@@ -38,14 +52,29 @@ static const std::unordered_map<std::string, std::string> instances =
 
 };
 
+// generates a Polytope from a poset
+/// @tparam Polytope Type of returned polytope
+template <class Polytope>
+Polytope get_orderpoly(Poset &poset) {
+    typedef typename Polytope::PointType Point;
+
+    OrderPolytope<Point> OP(poset);
+    if constexpr (std::is_same< Polytope, OrderPolytope<Point> >::value ) {
+        return OP;
+    } else {
+        Polytope HP(OP.dimension(), OP.get_full_mat(), OP.get_vec());
+        return HP;
+    }
+}
+
 // generates an Order Polytope from an instance name
 // Instances taken from: https://github.com/ttalvitie/le-counting-practice
 /// @tparam Polytope Type of returned polytope
 template <class Polytope>
 Polytope generate_orderpoly(std::string& instance_name) {
     std::stringstream in_ss(instances.at(instance_name));
     Poset poset = read_poset_from_file_adj_matrix(in_ss).second;
-    return Polytope(poset);
+    return get_orderpoly<Polytope>(poset);
 }
 
 // Generates a cube as an Order Polytope
@@ -56,8 +85,50 @@ Polytope generate_cube_orderpoly(unsigned int dim) {
 
     RV order_relations;
     Poset poset(dim, order_relations);
-    Polytope OP(poset);
-    return OP;
+    return get_orderpoly<Polytope>(poset);
+}
+
+// Generates a random Order Polytope with given dimension and number of facets
+/// @tparam Polytope Type of returned polytope
+/// @tparam RNGType RNGType Type
+template <class Polytope, typename NT>
+Polytope random_orderpoly(unsigned int dim, unsigned int m, int seed = std::numeric_limits<int>::signaling_NaN()) {
+
+    typedef typename Poset::RV RV;
+
+    int rng_seed = std::chrono::system_clock::now().time_since_epoch().count();
+    if (!isnan(seed)) {
+        rng_seed = seed;
+    }
+
+    typedef BoostRandomNumberGenerator<boost::mt19937, NT> RNG;
+    RNG rng(dim);
+    rng.set_seed(rng_seed);
+
+
+    std::vector<unsigned int> order(dim);
+    for(int i = 0; i < dim; ++i) {
+        order[i] = i;
+    }
+    boost::mt19937 shuffle_rng(rng_seed);
+    std::shuffle(order.begin(), order.end(), shuffle_rng);
+
+
+    RV order_relations;
+    for(int i = 0; i < m - 2 * dim; ++i) {
+        unsigned int x = rng.sample_uidist();
+        unsigned int y = rng.sample_uidist();
+        while(x == y) {
+            y = rng.sample_uidist();
+        }
+        if(x > y)
+            std::swap(x, y);
+        order_relations.push_back(std::make_pair(order[x], order[y]));
+    }
+
+
+    Poset poset(dim, order_relations);
+    return get_orderpoly<Polytope>(poset);
 }
 
 #endif

include/misc/poset.h

@@ -5,6 +5,7 @@
 // Copyright (c) 2020-2021 Vaibhav Thakkar
 
 // Contributed and/or modified by Vaibhav Thakkar, as part of Google Summer of Code 2021 program.
+// Contributed and/or modified by Luca Perju, as part of Google Summer of Code 2024 program.
 
 // Licensed under GNU LGPL.3, see LICENCE file
 
@@ -25,6 +26,36 @@ class Poset {
     unsigned int n;  // elements will be from 0 to n-1
     RV order_relations;     // pairs of form a <= b
 
+    static void sorted_list(std::vector<unsigned int> &res, const unsigned int &n, const RV &relations)
+    {
+        std::vector<std::vector<unsigned int> > adjList(n);
+        std::vector<unsigned int> indegree(n, 0);
+
+        for(auto x: relations) {
+            adjList[x.first].push_back(x.second);
+            indegree[x.second] += 1;
+        }
+
+        std::queue<unsigned int> q;
+        for(unsigned int i=0; i<n; ++i) {
+            if(indegree[i] == 0)
+                q.push(i);
+        }
+
+        while(!q.empty()) {
+            unsigned int curr = q.front();
+            res.push_back(curr);
+            q.pop();
+
+            for(unsigned int i=0; i<adjList[curr].size(); ++i) {
+                unsigned int adj_idx = adjList[curr][i];
+                indegree[adj_idx] -= 1;
+                if(indegree[adj_idx] == 0)
+                    q.push(adj_idx);
+            }
+        }
+    }
+
 public:
     Poset() {}
 
@@ -44,7 +75,12 @@ class Poset {
                 throw "invalid elements in order relations";
         }
 
-        // TODO: Check if corresponding DAG is actually acyclic
+        std::vector<unsigned int> order;
+        sorted_list(order, n, relations);
+
+        if(order.size() < n) {
+            throw "corresponding DAG is not acyclic";
+        }
 
         return relations;
     }
@@ -96,34 +132,8 @@ class Poset {
 
     std::vector<unsigned int> topologically_sorted_list() const
     {
-        std::vector<std::vector<unsigned int> > adjList(n);
-        std::vector<unsigned int> indegree(n, 0);
-
-        for(auto x: order_relations) {
-            adjList[x.first].push_back(x.second);
-            indegree[x.second] += 1;
-        }
-
-        std::queue<unsigned int> q;
-        for(unsigned int i=0; i<n; ++i) {
-            if(indegree[i] == 0)
-                q.push(i);
-        }
-
         std::vector<unsigned int> res;
-        while(!q.empty()) {
-            unsigned int curr = q.front();
-            res.push_back(curr);
-            q.pop();
-
-            for(unsigned int i=0; i<adjList[curr].size(); ++i) {
-                unsigned int adj_idx = adjList[curr][i];
-                indegree[adj_idx] -= 1;
-                if(indegree[adj_idx] == 0)
-                    q.push(adj_idx);
-            }
-        }
-
+        sorted_list(res, n, order_relations);
         return res;
     }
 };