How to write a summation code when the k is not equal to j
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yang-En Hsiao
on 17 Jan 2019
Commented: Debnath Goswami
on 28 Sep 2020
I want to write the code like this,and the rage of k is 1 to K,but i don't know how to write the " j is not equal to k" this summation code,can anyone show me how to write it ?
![不等於.PNG](https://www.mathworks.com/matlabcentral/answers/uploaded_files/144647/%E4%B8%8D%E7%AD%89%E6%96%BC.png)
Accepted Answer
Image Analyst
on 3 Feb 2019
yang-En, haven't heard from you. If the vectorized approach above is to confusing to you then try this simple and intuitive for loop. It basically uses the "continue" command to skip interations where j = k.
numPoints = 3; % Whatever...
lambda = randi(9, 1, numPoints) % Whatever...
f = randi(9, 1, numPoints) % Whatever...
h = randi(9, 1, numPoints) % Whatever...
K = length(lambda)
outerSum = 0;
for k = 1 : K
innerSum = 0;
% Do the inner sum over j with j not equal to k
for j = 1 : length(h)
if j == k
continue; % Skip this iteration
end
innerSum = innerSum + h(j) * f(k);
end
outerSum = outerSum + lambda(k) * innerSum;
end
outerSum % Spew out to the command window so we can see what it is.
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More Answers (1)
Torsten
on 17 Jan 2019
If all arrays involved have K elements, you can use
h = ...;
lambda = ...;
f = ...;
S = sum(h);
H = S-h ;
result = sum(lambda.*f.*H)
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