How to solve the double summation of the given expression

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vivek raja 2017-8-24

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https://ww2.mathworks.cn/matlabcentral/answers/353879-how-to-solve-the-double-summation-of-the-given-expression

评论： Yago Moreno 2019-9-5

I am unable to find out how can we find the double summation of the expression which has a lot of variables in it

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Jan 2017-8-24

What have you tried so far? I would not call this "a lot of" variables, but as long as you do not explain their meaning, posting code is based on guessing only. Please provide any details.

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Answer 1

njj1 2017-8-24

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编辑：njj1 2017-8-24

在 MATLAB Online 中打开

A blunt force method would be to have two for loops, one nested in the other. In the inner for loop, sum over the 'i' variables, and in the outer loop sum over the 'p' variables. This could look like:

AF = [];
for p=1:length(P)
    for i=1:Np
        AF = AF + I(p,i)*exp(1i*k*r(p)*sin(theta)*cos(phi0 - phi(p,i)) + alpha(p,i))
    end
end
AF = 1 + AF;

A more elegant solution would use matrix operations.

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Yago Moreno 2019-9-5

Hi njj1,

I was wondering how you would use matrix operations for double sums. Could you give more details or re-direct me to another post? I have not found posts explaining this method.

Thanks!

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