making sure the champion is only updated if allocation is succesfull

src/population.cpp

@@ -593,20 +593,18 @@ void population::push_back_impl(T &&x, U &&f)
     auto x_copy(std::forward<T>(x));
     auto f_copy(std::forward<U>(f));
 
-    // update_champion() either throws before modfying anything, or it completes successfully. The rest is noexcept.
-    update_champion(x_copy, f_copy);
+    auto n = pop.size();
     try {
         m_ID.push_back(new_id);
         m_x.push_back(std::move(x_copy));
         m_f.push_back(std::move(f_copy));
     } catch (...) {
-        auto n = m_ID.size();
-        n = std::min(n, m_x.size());
-        n = std::min(n, m_f.size());
         m_ID.resize(n);
         m_x.resize(n);
         m_f.resize(n);
     }
+    // update_champion() either throws before modfying anything, or it completes successfully. The rest is noexcept.
+    update_champion(pop.get_x(n+1), pop.get_f(n+1));
 }
 
 // Short routine to update the champion. Does nothing if the problem is MO