How to filter the following vector from multiple vectors?

How to filter the following vector from multiple vectors?

I want to do the following for each matrix stored in M

suppose each vector is named as the following in Matrix M: [deltaX

deltaY

1]

I want to filter the vector that satisfy the following conditions:

if abs(deltaY) is less than threshold for example 32

then select that vectors/vector

after that if there are more than selected vectors, filter them as the following:

select the vector that has the min deltaX

*The out should be 23 separated vectors each corrosponding to its matrix

[Jan]

What does this mean: "suppose the each vector is named as the following in Matrix MM"?

Would it be impolite if I reply although I'm neither Matt J nor Star Strider?! Please avoid addressing specific persons in the forum except if you have really good reasons.

Answer 1

[Jon]

I think this does what you describe

% filter matrix mm

% parameters
threshold = 32

% extract the matrix out of the cell array MM
load MM.mat
mm = MM{1}

% find all of the columns where the value in the second row is over
% threshold
result1 = mm(:,abs(mm(2,:))>threshold)

% now pick the one with the smallest value of "delta x" (first row)
[~,idx] = min(result1(1,:));
result2 = result1(:,idx)

For the calculation of result2, which pick the one with the minimum value in the first row, I wasn't sure from your description if you wanted the minimum of the actual values, or the minimum absolute value. I picked the minimum, so it is one with a negative value. You can modify the code accordingly.

[Jon]

Oops, I read your description more carefully, and realized I selected columns which were greater than the threshold, you wanted ones that were less, so change the corresponding line to

result1 = mm(:,abs(mm(2,:))<=threshold)

Anyhow, it looks like my answer is very similar to @Jan's. By the time I posted my answer I guess he had already put his in. So I would go with @Jan's answer

[M]

@Jon, thank you so much.

Can you please help in iterating your code For all M matrix that I added to the question please.

[Jon]

% filter matrices in M.mat

% parameters
threshold = 32

% load the cell array of matrices to be filtered
load M.mat

% loop through matrices filtering each one
% accumulate results (selected column) in a matrix where each column is the
% selected column from the corresponding matrix in M
numFilter = numel(M); % number of matrices to be filtered
R = zeros(3,numFilter); % preallocate array to hold results
for k = 1:numFilter
    % extract the kth matrix to be filtered
    m = M{k};
    
    % find all of the columns where the value in the second row is less than
    % threshold
    result1 = m(:,abs(m(2,:))<threshold);
    
    % now pick the one with the smallest value of "delta x" (first row)
    [~,idx] = min(result1(1,:));
    
    % store the result
    R(:,k) = result1(:,idx);
end

Answer 2

[Jan]

Maybe:

V = MM(:, abs(MM(2, :)) < 32);
[~, index] = min(V(1, :));
W = V(:, index)