Harris Hawks Optimization (HHO)

HHO is a population-based, gradient-free optimization algorithm. In 2019, Future Generation Computer Systems (FGCS) has published the HHO algorithm. The main inspiration of HHO is the cooperative behavior and chasing style of Harris’ hawks in nature called “surprise pounce”. 

Team Members:
Huiling Chen


Background Facts

Harris hawks can reveal a variety of chasing patterns based on the dynamic nature of scenarios and escaping patterns of the rabbit.


Mathematical model and structure

The following features can theoretically assist us in realizing why the proposed HHO can be beneficial in exploring or exploiting the search space of a given optimization problem:

  • Escaping energy parameter has a dynamic randomized time-varying nature, which can further boost the exploration and exploitation patterns of HHO. This factor also requires HHO to perform a smooth transition between exploration and exploitation.
  • Different diversification mechanisms with regard to the average location of hawks can boost the exploratory behavior of HHO in initial iterations.
  • Different LF-based patterns with short-length jumps enhance the exploitative behaviors of HHO when conducting a local search.
    The progressive selection scheme assists search agents to progressively improve their position and only select a better position, which can improve the quality of solutions and intensification powers of HHO during the course of iterations.
  • HHO utilizes a series of searching strategies based on and parameters and then, it selects the best movement step. This capability has also a constructive impact on the exploitation potential of HHO.
    The randomized jump strength can assist candidate solutions in balancing the exploration and exploitation tendencies.
  • The use of adaptive and time-varying parameters allows HHO to handle difficulties of a search space including local optimal solutions, multi-modality, and deceptive optima.

Source codes of HHO algorithm

  • Matlab source codes of HHO are publicly available here
  • Latex codes of HHO section including the Pseudo-code are publicly available here
  • Visio files of figures in HHO section are publicly available here
You can download the paper from here If you do not have any access to Sciencedirect, please drop Dr. Ali Asghar Heidari an e-mail here and he will send you the paper. If you have any questions or something to share, please feel free to post it at the end of this page in the comment section.

If you have any question regarding the proposed HHO or you need any help in codes of HHO or any assistant in modeling your problem or need any help in preparing your proposal and manuscript, please simply drop an email to first author Dr. Ali Asghar Heidari e-mail here and he will help you online.

We will always be happy to cooperate with you if you have any new idea or proposal on the HHO algorithm. You can contact us or first author Dr. Ali Asghar Heidari. Let’s enjoy finding the optimal solutions to your real-world problems.

Explore and run HHO interactively

21 Comments on "Harris Hawks Optimization (HHO)"

  1. Thanks

  2. (Please ignore my previous comment, because some text are deleted due to the use of less than and greater than symbol)
    First of all, thank you for sharing this paper and source code. It is an excellent algorithm!
    Secondly, pardon me if I’m wrong, but I’ve found a different application on the perching strategies (Eq. 1). In the paper, the formula with rabbit location (Xrabbit) is used on perching based on other family members (q is less than 0.5), but in the Matlab code, it is used on perching on a random tall tree (q is greater than or equals to 0.5).
    Please kindly respond, as it would help me with my research. Thank you.

  3. Hello Ali,
    It is very interesting and effective algorithm requiring logic, skill and hard work to understand. But finally it will pay well in latest publications.
    Thanks for sharing the code and research paper.
    Great Work with Lots of Efforts !!!

  4. Thanks very much for you sharing the paper “Harris hawks optimization: Algorithm and applications” in Future Generation Computer Systems. It is an excellent optimization algorithm. I am very interesting in it. Furthermore, Thanks very much for you sharing the codes of the paper. From “http://www.alimirjalili.com/HHO.html and http://www.evo-ml.com/2019/03/02/hho”, I obtained the codes of some testing functions (F1-F23) of this paper, but I don’t find the codes of F24-F29 and the codes of solving the Engineering benchmark sets. I would like to see if you can offer them to me?
    Thank you for your understanding and kind assistance. Looking forward to your earliest reply with your good convenience.

    • Thank you so much Xia Li, happy to see your interests and attention in our HHO algorithm. Currently, the codes of F24-F29 and constrained versions of HHO in different languages are not publicly available and we will release as soon as possible. In any case, first, you can compare your results on constrained cases with available results on paper. You can follow the well=known and public penalty method to handle constraints. For F24-F29, you can find them on the website of CEC competitions.
      I hope you reach favorable results with HHO.

    • Hello ali;
      I work in woa algorithm.can you send information about exploration and exploitation in this algorithm and where is use this method?
      Thankyou

  5. is it possible to use this optimization in power system problems

    • Ali Asghar Heidari | April 30, 2019 at 10:14 am | Reply

      yes sure, you can apply this method to any problem, if you develop your objective function and insert it as an input to the HHO.

  6. Ali Asghar Heidari | March 26, 2019 at 7:31 pm | Reply

    Thanks for your nice feedback, we appreciate it

  7. Excellent optimization algorithm , than you for sharing codes, and paper

  8. Mohammad Jalali | March 9, 2019 at 2:27 pm | Reply

    Excellent EA. Congratulations to Ali for writing such great EA. Good luck

  9. First, the content style is pleasing: text, pictures, videos, embedded PDF papers are clear, neat and beautiful.
    Secondly, the content is concise and clear.
    Finally, the best thing is that the author gives us free downloads of all the resources involved in the paper.
    The work of conscience, praise for the author Ali Asghar Heidari !
    Give the thumbs-up!

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