diff --git a/cpp/switchchain_timeevol.cpp b/cpp/switchchain_timeevol.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..37f77c5fbd7808a43d60b7b08beec63ac35e5e9b
--- /dev/null
+++ b/cpp/switchchain_timeevol.cpp
@@ -0,0 +1,328 @@
+#include "exports.hpp"
+#include "graph.hpp"
+#include "powerlaw.hpp"
+#include <algorithm>
+#include <array>
+#include <fstream>
+#include <iostream>
+#include <numeric>
+#include <random>
+#include <vector>
+
+// Its assumed that u,v are distinct.
+// Check if all four vertices are distinct
+bool edgeConflicts(const Edge& e1, const Edge& e2) {
+    return (e1.u == e2.u || e1.u == e2.v || e1.v == e2.u || e1.v == e2.v);
+}
+
+class SwitchChain {
+  public:
+    SwitchChain()
+        : mt(std::random_device{}()), permutationDistribution(0.5)
+    // permutationDistribution(0, 2)
+    {
+        // random_device uses hardware entropy if available
+        // std::random_device rd;
+        // mt.seed(rd());
+    }
+    ~SwitchChain() {}
+
+    bool initialize(const Graph& gstart) {
+        if (gstart.edgeCount() == 0)
+            return false;
+        g = gstart;
+        edgeDistribution.param(
+            std::uniform_int_distribution<>::param_type(0, g.edgeCount() - 1));
+        return true;
+    }
+
+    bool doMove() {
+        int e1index, e2index;
+        int timeout = 0;
+        // Keep regenerating while conflicting edges
+        do {
+            e1index = edgeDistribution(mt);
+            e2index = edgeDistribution(mt);
+            if (++timeout % 100 == 0) {
+                std::cerr << "Warning: sampled " << timeout
+                          << " random edges but they keep conflicting.\n";
+            }
+        } while (edgeConflicts(g.getEdge(e1index), g.getEdge(e2index)));
+
+        // Consider one of the three possible permutations
+        // 1) e1.u - e1.v and e2.u - e2.v (original)
+        // 2) e1.u - e2.u and e1.v - e2.v
+        // 3) e1.u - e2.v and e1.v - e2.u
+        bool switchType = permutationDistribution(mt);
+        return g.exchangeEdges(e1index, e2index, switchType);
+    }
+
+    Graph g;
+    std::mt19937 mt;
+    std::uniform_int_distribution<> edgeDistribution;
+    //std::uniform_int_distribution<> permutationDistribution;
+    std::bernoulli_distribution permutationDistribution;
+};
+
+void getTriangleDegrees(const Graph& g) {
+    std::vector<std::array<std::size_t,3>> trids;
+    const auto& adj = g.getAdj();
+    int triangles = 0;
+    for (auto& v : adj) {
+        for (unsigned int i = 0; i < v.size(); ++i) {
+            for (unsigned int j = i + 1; j < v.size(); ++j) {
+                if (g.hasEdge({v[i], v[j]})) {
+                    ++triangles;
+                    std::array<std::size_t, 3> ds = {{v.size(), adj[v[i]].size(),
+                                                     adj[v[j]].size()}};
+                    std::sort(ds.begin(), ds.end());
+                    trids.push_back(ds);
+                }
+            }
+        }
+    }
+    assert(triangles % 3 == 0);
+    return;
+}
+
+//
+// Assumes degree sequence does NOT contain any zeroes!
+//
+// method2 = true  -> take highest degree and finish its pairing completely
+// method2 = false -> take new highest degree after every pairing
+template <typename RNG>
+bool greedyConfigurationModel(DegreeSequence& ds, Graph& g, RNG& rng, bool method2) {
+    // Similar to Havel-Hakimi but instead of pairing up with the highest ones
+    // that remain, simply pair up with random ones
+    unsigned int n = ds.size();
+
+    // degree, vertex index
+    std::vector<std::pair<unsigned int, unsigned int>> degrees(n);
+    for (unsigned int i = 0; i < n; ++i) {
+        degrees[i].first = ds[i];
+        degrees[i].second = i;
+    }
+
+    std::vector<decltype(degrees.begin())> available;
+    available.reserve(n);
+
+    // Clear the graph
+    g.reset(n);
+
+    while (!degrees.empty()) {
+        std::shuffle(degrees.begin(), degrees.end(), rng);
+        // Get the highest degree:
+        // If there are multiple highest ones, we pick a random one,
+        // ensured by the shuffle.
+        // The shuffle is needed anyway for the remaining part
+        unsigned int dmax = 0;
+        auto uIter = degrees.begin();
+        for (auto iter = degrees.begin(); iter != degrees.end(); ++iter) {
+            if (iter->first >= dmax) {
+                dmax = iter->first;
+                uIter = iter;
+            }
+        }
+
+        if (dmax > degrees.size() - 1)
+            return false;
+
+        if (dmax == 0) {
+            std::cerr << "ERROR 1 in GCM.\n";
+        }
+
+        unsigned int u = uIter->second;
+
+        if (method2) {
+            // Take the highest degree out of the vector
+            degrees.erase(uIter);
+
+            // Now assign randomly to the remaining vertices
+            // Since its shuffled, we can pick the first 'dmax' ones
+            auto vIter = degrees.begin();
+            while (dmax--) {
+                if (vIter->first == 0)
+                    std::cerr << "ERROR in GCM2.\n";
+                if (!g.addEdge({u, vIter->second}))
+                    std::cerr << "ERROR. Could not add edge in GCM2.\n";
+                vIter->first--;
+                if (vIter->first == 0)
+                    vIter = degrees.erase(vIter);
+                else
+                    vIter++;
+            }
+        } else {
+            // Pair with a random vertex that is not u itself and to which
+            // u has not paired yet!
+            available.clear();
+            for (auto iter = degrees.begin(); iter != degrees.end(); ++iter) {
+                if (iter->second != u && !g.hasEdge({u, iter->second}))
+                    available.push_back(iter);
+            }
+            if (available.empty())
+                return false;
+            std::uniform_int_distribution<> distr(0, available.size() - 1);
+            auto vIter = available[distr(rng)];
+            // pair u to v
+            if (vIter->first == 0)
+                std::cerr << "ERROR 2 in GCM1.\n";
+            if (!g.addEdge({u, vIter->second}))
+                std::cerr << "ERROR. Could not add edge in GCM1.\n";
+            // Purge anything with degree zero
+            // Be careful with invalidating the other iterator!
+            // Degree of u is always greater or equal to the degree of v
+            if (dmax == 1) {
+                // Remove both
+                // Erasure invalidates all iterators AFTER the erased one
+                if (vIter > uIter) {
+                    degrees.erase(vIter);
+                    degrees.erase(uIter);
+                } else {
+                    degrees.erase(uIter);
+                    degrees.erase(vIter);
+                }
+            } else {
+                // Remove only v if it reaches zero
+                uIter->first--;
+                vIter->first--;
+                if (vIter->first == 0)
+                    degrees.erase(vIter);
+            }
+            //degrees.erase(std::remove_if(degrees.begin(), degrees.end(),
+            //                             [](auto x) { return x.first == 0; }));
+        }
+    }
+    return true;
+}
+
+int main(int argc, char* argv[]) {
+    // Generate a random degree sequence
+    std::mt19937 rng(std::random_device{}());
+
+    // Goal:
+    // Degrees follow a power-law distribution with some parameter tau
+    // Expect:  #tri = const * n^{ something }
+    // The goal is to find the 'something' by finding the number of triangles
+    // for different values of n and tau
+    //float tauValues[] = {2.5f};
+    float tauValues[] = {2.1f, 2.2f, 2.3f, 2.4f, 2.5f, 2.6f, 2.7f, 2.8f, 2.9f};
+
+    Graph g;
+    Graph g1;
+    Graph g2;
+
+    std::ofstream outfile;
+
+    if (argc >= 2)
+        outfile.open(argv[1]);
+    else   
+        outfile.open("graphdata_mixingtime.m");
+
+    if (!outfile.is_open()) {
+        std::cout << "ERROR: Could not open output file.\n";
+        return 1;
+    }
+
+    outfile << '{';
+    bool outputComma = false;
+
+    for (int numVertices = 1000; numVertices <= 1000; numVertices += 1000) {
+        for (float tau : tauValues) {
+
+            DegreeSequence ds(numVertices);
+            powerlaw_distribution degDist(tau, 1, numVertices);
+            //std::poisson_distribution<> degDist(12);
+
+            // For a single n,tau take samples over several instances of
+            // the degree distribution.
+            // 500 samples seems to give reasonable results
+            for (int degreeSample = 0; degreeSample < 5; ++degreeSample) {
+                // Generate a graph
+                // might require multiple tries
+                for (int i = 1; ; ++i) {
+                    std::generate(ds.begin(), ds.end(),
+                                  [&degDist, &rng] { return degDist(rng); });
+                    // First make the sum even
+                    unsigned int sum = std::accumulate(ds.begin(), ds.end(), 0);
+                    if (sum % 2) {
+                        continue;
+                        // Can we do this: ??
+                        ds.back()++;
+                    }
+
+                    if (g.createFromDegreeSequence(ds))
+                        break;
+
+                    // When 10 tries have not worked, output a warning
+                    if (i % 10 == 0) {
+                        std::cerr << "Warning: could not create graph from "
+                                     "degree sequence. Trying again...\n";
+                    }
+                }
+
+                // Multiple runs from the same degree sequence
+                for (int i = 0; i < 5; ++i) {
+
+                SwitchChain chain;
+                if (!chain.initialize(g)) {
+                    std::cerr << "Could not initialize Markov chain.\n";
+                    return 1;
+                }
+
+                std::cout << "Running n = " << numVertices << ", tau = " << tau
+                          << ". \t" << std::flush;
+
+                //int mixingTime = (32.0f - 26.0f*(tau - 2.0f)) * numVertices; //40000;
+                //constexpr int measurements = 50;
+                //constexpr int measureSkip =
+                //    200; // Take a sample every ... steps
+                int mixingTime = 0;
+                constexpr int measurements = 50000;
+                constexpr int measureSkip = 1;
+
+
+                int movesTotal = 0;
+                int movesSuccess = 0;
+
+                int triangles[measurements];
+
+                for (int i = 0; i < mixingTime; ++i) {
+                    ++movesTotal;
+                    if (chain.doMove()) {
+                        ++movesSuccess;
+                    }
+                }
+
+                for (int i = 0; i < measurements; ++i) {
+                    for (int j = 0; j < measureSkip; ++j) {
+                        ++movesTotal;
+                        if (chain.doMove()) {
+                            ++movesSuccess;
+                        }
+                    }
+                    triangles[i] = chain.g.countTriangles();
+                }
+
+                std::cout << '('
+                          << 100.0f * float(movesSuccess) / float(movesTotal)
+                          << "% successrate). " << std::flush;
+                // std::cout << std::endl;
+
+                if (outputComma)
+                    outfile << ',' << '\n';
+                outputComma = true;
+
+                std::sort(ds.begin(), ds.end());
+                outfile << '{' << '{' << numVertices << ',' << tau << '}';
+                outfile << ',' << triangles;
+                outfile << ',' << ds;
+                outfile << '}' << std::flush;
+
+                std::cout << std::endl;
+                }
+            }
+        }
+    }
+    outfile << '}';
+    return 0;
+}