diff --git a/cpp/switchchain_dsp.cpp b/cpp/switchchain_dsp.cpp
index a9f0ff85bedb5c92f59954c114c0b572099830f1..268504b74542a89f3b293d016b0335c7511d9f3f 100644
--- a/cpp/switchchain_dsp.cpp
+++ b/cpp/switchchain_dsp.cpp
@@ -77,7 +77,7 @@ double getProperty(const DegreeSequence& ds) {
 
     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);
+            vals[i][j] = 1.0 - std::exp(-(ds[i] * ds[j] * factor));
         }
     }