I'm implementing flower pollination algorithm, but I find Yang's original code not to be in accordance with the results presented in the paper. Following is the Levy function defined in his code:
function L=Levy(d)
% Levy exponent and coefficient
% For details, see Chapter 11 of the following book:
% Xin-She Yang, Nature-Inspired Optimization Algorithms, Elsevier, (2014).
beta=3/2;
sigma=(gamma(1+beta)*sin(pi*beta/2)/(gamma((1+beta)/2)*beta*2^((beta-1)/2)))^(1/beta);
u=randn(1,d)*sigma;
v=randn(1,d);
step=u./abs(v).^(1/beta);
L=0.01*step;
Please comment on the correctness of this code. Thank you.
Which Levy distribution do you need?
If you are interested in Levy alpha-stable distributions, you could check the following links:
http://www.mathworks.co.uk/matlabcentral/fileexchange/13619-toolbox-non-local-means/content/toolbox_nlmeans/toolbox/stabrnd.m
http://academic2.american.edu/~jpnolan/stable/stable.html
Ultimately, you should consult the original paper by Chambers, Mallow and Stuck:
J.M. Chambers, C.L. Mallows and B.W. Stuck, "A Method for Simulating Stable Random Variables," JASA 71 (1976): 340-4.
I hope this helps.
What do you mean with randn(1,d)? They should be normal variables with average equal to zero and variance equal to one. Moreover the expression you are writing for sigma, is actually the one for sigma^2.
This is part of code in C. I hope it will be helpful for you
double alpha=2;
int itr=1;
while(itr
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