diff --git a/examples/example.cpp b/examples/example.cpp
index e81b5646..89cb2311 100644
--- a/examples/example.cpp
+++ b/examples/example.cpp
@@ -13,7 +13,7 @@
 //    limitations under the License.
 
 #include <iostream>
-#include "../include/find_embedding.hpp"
+#include "../include/find_embedding/find_embedding.hpp"
 
 class MyCppInteractions : public find_embedding::LocalInteraction {
   public:
@@ -21,7 +21,8 @@ class MyCppInteractions : public find_embedding::LocalInteraction {
     void cancel() { _canceled = true; }
 
   private:
-    virtual void displayOutputImpl(const std::string& mess) const { std::cout << mess << std::endl; }
+    void displayOutputImpl(const std::string& mess) const override { std::cout << mess << std::endl; }
+    void displayErrorImpl(const std::string& mess) const override { std::cout << mess << std::endl; }
     virtual bool cancelledImpl() const { return _canceled; }
 };
 
diff --git a/include/find_embedding/find_embedding.hpp b/include/find_embedding/find_embedding.hpp
index 6f61374d..3b6b3b7c 100644
--- a/include/find_embedding/find_embedding.hpp
+++ b/include/find_embedding/find_embedding.hpp
@@ -85,8 +85,8 @@ class parameter_processor {
 
     vector<int> _filter_fixed_vars() {
         vector<int> unscrew(num_vars);
-        assert(var_fixed_unscrewed.size() == num_vars);
-        assert(num_fixed < num_vars);
+        iszero(var_fixed_unscrewed.size() == num_vars);
+        iszero(num_fixed < num_vars);
         for (unsigned int i = 0, front = 0, back = num_vars - num_fixed; i < num_vars; i++) {
             if (var_fixed_unscrewed[i]) {
                 unscrew[back++] = i;
diff --git a/include/find_embedding/util.hpp b/include/find_embedding/util.hpp
index e4c50927..8adbe16f 100644
--- a/include/find_embedding/util.hpp
+++ b/include/find_embedding/util.hpp
@@ -94,10 +94,10 @@ class LocalInteraction {
   public:
     virtual ~LocalInteraction() {}
     //! Print a message through the local output method
-    void displayOutput(int loglevel, const string& msg) const { displayOutputImpl(loglevel, msg); }
+    void displayOutput(int loglevel, const string& msg) const { displayOutputImpl(msg); }
 
     //! Print an error through the local output method
-    void displayError(int loglevel, const string& msg) const { displayErrorImpl(loglevel, msg); }
+    void displayError(int loglevel, const string& msg) const { displayErrorImpl(msg); }
 
     //! Check if someone is trying to cancel the embedding process
     int cancelled(const clock::time_point stoptime) const {
@@ -108,10 +108,10 @@ class LocalInteraction {
 
   private:
     //! Print the string to a binding specified sink
-    virtual void displayOutputImpl(int loglevel, const string&) const = 0;
+    virtual void displayOutputImpl(const string&) const = 0;
 
     //! Print the error to a binding specified sink
-    virtual void displayErrorImpl(int loglevel, const string&) const = 0;
+    virtual void displayErrorImpl(const string&) const = 0;
 
     //! Check if the embedding process has timed out.
     virtual bool timedOutImpl(const clock::time_point stoptime) const { return clock::now() >= stoptime; }