diff --git a/cpp/Makefile b/cpp/Makefile
index 1b149ffc3945e40ab8790fdecdf0f12de52ca651..bcffd1cbe550055ad9bdc9b98855dafa23afd236 100644
--- a/cpp/Makefile
+++ b/cpp/Makefile
@@ -5,7 +5,7 @@ INCLUDES += -I.
 CXXFLAGS += -std=c++14 -O3 -Wall -Wextra -Wfatal-errors -Werror -pedantic -Wno-deprecated-declarations $(INCLUDES)
 
 
-all: switchchain switchchain_exponent switchchain_initialtris
+all: switchchain switchchain_exponent switchchain_initialtris switchchain_dsp
 
 
 switchchain:
@@ -17,6 +17,9 @@ switchchain_exponent:
 switchchain_initialtris:
 
 
+switchchain_dsp:
+
+
 # target : dep1 dep2 dep3
 # 	$@ = target
 # 	$< = dep1
diff --git a/cpp/switchchain_dsp.cpp b/cpp/switchchain_dsp.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..a9f0ff85bedb5c92f59954c114c0b572099830f1
--- /dev/null
+++ b/cpp/switchchain_dsp.cpp
@@ -0,0 +1,201 @@
+#include "exports.hpp"
+#include "graph.hpp"
+#include "powerlaw.hpp"
+#include <algorithm>
+#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;
+};
+
+double getProperty(const DegreeSequence& ds) {
+    std::vector<std::vector<double>> vals(ds.size());
+    for (auto& v : vals) {
+        v.resize(ds.size(), 0);
+    }
+
+    auto D = 0u;
+    for (auto d : ds)
+        D += d;
+
+    double factor = 1.0 / double(D);
+
+    for (auto i = 0u; i < ds.size(); ++i) {
+        for (auto j = i + 1; j < ds.size(); ++j) {
+            vals[i][j] = 1.0 - std::exp(-ds[i] * ds[j] * factor);
+        }
+    }
+
+    double result = 0.0;
+    for (auto i = 0u; i < ds.size(); ++i) {
+        for (auto j = i + 1; j < ds.size(); ++j) {
+            for (auto k = j + 1; k < ds.size(); ++k) {
+                result += vals[i][j] * vals[j][k] * vals[i][k];
+            }
+        }
+    }
+    return result;
+}
+
+int main() {
+    // 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[] = {2.1f, 2.5f, 2.9f};
+
+    Graph g;
+    Graph g1;
+    Graph g2;
+
+    std::ofstream outfile("graphdata_dsp.m");
+    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 < 2000; ++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";
+                    }
+                }
+
+                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*(32.0f - 10.0f*(tau - 2.0f)) * numVertices; //40000;
+                constexpr int measurements = 50;
+                constexpr int measureSkip =
+                    200; // Take a sample every ... steps
+
+                int movesDone = 0;
+
+                long long trianglesTotal = 0;
+
+                for (int i = 0; i < mixingTime; ++i) {
+                    if (chain.doMove())
+                        ++movesDone;
+                }
+                for (int i = 0; i < measurements; ++i) {
+                    for (int j = 0; j < measureSkip; ++j)
+                        if (chain.doMove())
+                            ++movesDone;
+                    trianglesTotal += chain.g.countTriangles();
+                }
+
+                std::cout << movesDone << '/' << mixingTime + measurements * measureSkip
+                          << " moves succeeded ("
+                          << 100.0f * float(movesDone) /
+                                 float(mixingTime + measurements * measureSkip)
+                          << "%).";
+                std::cout << std::flush;
+                //std::cout << std::endl;
+
+                if (outputComma)
+                    outfile << ',' << '\n';
+                outputComma = true;
+
+                float avgTriangles =
+                    float(trianglesTotal) / float(measurements);
+                outfile << '{' << '{' << numVertices << ',' << tau << '}';
+                outfile << ',' << avgTriangles;
+                outfile << ',' << getProperty(ds) << '}' << std::flush;
+
+                std::cout << std::endl;
+            }
+        }
+    }
+    outfile << '}';
+    return 0;
+}