ActivityDrivenModel: fixed sign in homophily

src/models/ActivityDrivenModel.cpp

@@ -49,12 +49,12 @@ void Seldon::ActivityAgentModel::iteration()
         {
 
             // Implement the weight for the probability of agent `idx_agent` contacting agent `j`
-            // Not normalised since, this is taken care of by the reservoir sampling
+            // Not normalised since this is taken care of by the reservoir sampling
             auto weight_callback = [idx_agent, this]( size_t j ) {
                 if( idx_agent == j ) // The agent does not contact itself
                     return 0.0;
                 return std::pow(
-                    std::abs( this->agents[idx_agent].data.opinion - this->agents[j].data.opinion ), this->homophily );
+                    std::abs( this->agents[idx_agent].data.opinion - this->agents[j].data.opinion ), -this->homophily );
             };
 
             Seldon::reservoir_sampling_A_ExpJ( m, network.n_agents(), weight_callback, contacted_agents, gen );