# can someone help to write this the rosenbrock function for PSO and DE

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Cesario Anderson Mouzinho on 17 Apr 2024
Answered: Aman on 22 Apr 2024
function f = rosenbrock_function(x)
d = length(x);
f = 0;
for i = 1:(d-1)
f = f + 100*(x(i+1) - x(i)^2)^2 + (1 - x(i))^2;
Sam Chak on 17 Apr 2024
Could you please, with the least efforts, provide the basic Rosenbrock function in MATLAB code? You can click the indentation icon to insert the code. This will enable other users to review and provide guidance on which function to use for summing up the terms.
function f = rosenbrock(x)
f = ...;
end
Cesario Anderson Mouzinho on 17 Apr 2024
function f = rosenbrock_function(x)
d = length(x);
f = 0;
for i = 1:(d-1)
f = f + 100*(x(i+1) - x(i)^2)^2 + (1 - x(i))^2;

Aman on 22 Apr 2024
Hi Cesario,
As per my understanding, you want to use the rosenbrock function as the fitness function in the particle swarm optimization (PSO) and differential evolution (DE) functions for evaluating their convergence and performance.
The way you have implemented it is correct, so while calculating the fitness of a particle, you just need to call this function and pass the position vector of the particle as a parameter.
You can refer to the below video, which also explains how to use this function in a number of ways:
I hope this helps!