could anyone hep me to clear my doubt

In Particle swarm optimization for minimization, the global best is initialized to inf ;

for maximization the global best is initialized to -inf;

But in general inf is a largest value and how it can be used for minimization

and -inf is a smallest value and how it can be used for maximization.

Could anyone please clarify it.

Answer 1

[Rik]

Because inf is the extreme, you can use it to find the next value in your data. As an example, the code below finds the maximum value in a vector:

max_val=-inf;
data=rand(1,100);
for n=1:numel(data)
    if data(n)>max_val%is bigger than current max?
        max_val=data(n);%store new max
    end
end

Now the -inf will be replaced by the actual larger value once it finds one. The only case where it will stay -inf is when all values in the data are -inf, in which case it is indeed the maximum value.

Minimization works the same in the reverse case.

[Rik]

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