How to match matrix elements for a condition?
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piston_pim_offset
on 22 Apr 2024
Commented: piston_pim_offset
on 24 Apr 2024
I am working on App Designer. I have a matrix and want to match the elements 3 by 3 with a condition. The condition is that addition of 3 elements must be near at a value.
I already can match them by making the addition from minimum to maximum, but it does not seem to be optimal. So, I want them to be around a value.
2 Comments
Dyuman Joshi
on 22 Apr 2024
Use tolerance to compare -
in = [3 3.3 3.6 3.9];
check = 3.5;
tol = 0.3;
out = abs(in-check)<tol
Accepted Answer
Torsten
on 23 Apr 2024
Edited: Torsten
on 23 Apr 2024
If A becomes larger, this brute-force way of solving will become intractable.
A = [15 25 36 17 48 59 31 64 18 21 97 84 31 64 15];
target = 100;
C = nchoosek(1:numel(A),3);
P = arrayfun(@(i)sum(A(C(i,1:3))),1:size(C,1));
[~,I] = sort(abs(P-target));
sums = arrayfun(@(i)sum(A(C(I(i),:))),1:numel(I));
sums = sums(sums==sums(1));
n = numel(sums);
result = unique(sort(A(C(I(1:n),:)),2),'rows')
More Answers (1)
Hassaan
on 22 Apr 2024
Assuming a 1-dimensional array. Will check for sums of three consecutive elements that are close to a given value (target_sum) within a tolerance (tol).
% Example matrix (1D array)
A = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
% Target sum to match
target_sum = 15;
% Tolerance for matching sum
tol = 0.5;
% Length of the array
n = length(A);
% Pre-allocate the logical output array for matched cases
matches = false(1, n-2); % (n-2) because the last two elements can't start a triplet
% Iterate over the array to find matching triplets
for i = 1:n-2
% Calculate the sum of the current and next two elements
current_sum = sum(A(i:i+2));
% Check if the current sum is within the tolerance of the target sum
if abs(current_sum - target_sum) <= tol
matches(i) = true;
end
end
% Print matched triplets and their indices
matched_indices = find(matches);
for idx = matched_indices
fprintf('Match found at indices [%d, %d, %d]: [%d, %d, %d]\n', idx, idx+1, idx+2, A(idx), A(idx+1), A(idx+2));
end
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It's important to note that the advice and code are based on limited information and meant for educational purposes. Users should verify and adapt the code to their specific needs, ensuring compatibility and adherence to ethical standards.
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