**4. Conclusion**

After GA, PSO is the first and foremost algorithm which is the most successful algorithm especially for the solution of the continuous optimization problems. Subsequent algorithms using swarm intelligence nearly have the same ideas. All of them are population based, and all particles are distributed in the solution space. Particles have initial locations and velocities. They converge to the optimum solution using their swarm intelligence.

Although there have been improvements in the optimization algorithms using swarm intelligence, there is not a unique algorithm which is successful in all types of optimization problems. So the efforts trying to simulate the animal behaviors and swarm intelligence will continue. At the same time, developing hybrid algorithms will also continue until the best combination of the algorithms would be found.
