diff --git a/cpp/switchchain_spectrum.cpp b/cpp/switchchain_spectrum.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..5ccf1e5f81447b1789ee6e8c8fb717cbb325db12
--- /dev/null
+++ b/cpp/switchchain_spectrum.cpp
@@ -0,0 +1,142 @@
+#include "switchchain.hpp"
+#include "exports.hpp"
+#include "graph.hpp"
+#include "graph_gcm.hpp"
+#include "graph_spectrum.hpp"
+#include "powerlaw.hpp"
+#include <algorithm>
+#include <array>
+#include <fstream>
+#include <iostream>
+#include <numeric>
+#include <random>
+#include <vector>
+
+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[] = {2.1f, 2.2f, 2.3f, 2.4f, 2.5f, 2.6f, 2.7f, 2.8f, 2.9f};
+
+    Graph g;
+
+    std::ofstream outfile;
+
+    if (argc >= 2)
+        outfile.open(argv[1]);
+    else   
+        outfile.open("graphdata_spectrum.m");
+
+    if (!outfile.is_open()) {
+        std::cout << "ERROR: Could not open output file.\n";
+        return 1;
+    }
+
+    outfile << '{';
+    bool outputComma = false;
+
+    for (int numVertices = 500; numVertices <= 500; 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";
+                    }
+                }
+
+                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;
+
+                GraphSpectrum gs(g);
+
+                if (outputComma)
+                    outfile << ',' << '\n';
+                outputComma = true;
+
+                //std::sort(ds.begin(), ds.end());
+                outfile << '{' << '{' << numVertices << ',' << tau << '}';
+                outfile << ',' << triangles;
+                outfile << ',' << g.edgeCount();
+                outfile << ',' << gs.computeAdjacencySpectrum();
+                outfile << ',' << gs.computeLaplacianSpectrum();
+                outfile << '}' << std::flush;
+
+                std::cout << std::endl;
+            }
+        }
+    }
+    outfile << '}';
+    return 0;
+}