MATLAB: Eliminating Matrix Elements Which Exceeds Some Threshold with Using idx

eliminating matrix elementsrelevant points

I am working on a Radon transform algorithm, in my code i have a set of x,y values and i wanted to eliminate the x,y values which exceeds some certain values like -2 and 2 for example. For this purpose, i am using the code below but i couldn't get how it works. Is there anyone who can explain to me?

idx=any(A<-M/2 | A>M/2,2);

out=A(idx,:);

A(idx,:)=[];

Thanks in advance.

Best Answer

A is a Matrix of m rows by n columns, therefore, idx is going to be a logical vector of m rows by 1 column, if any element in the row of A is less than -M / 2 or greater than M / 2 then in that row the idx value will be 1 otherwise it will be 0.

in out those rows of A that were positive in idx are going to be saved and from those rows we want to get all the columns, and after that in those same rows that were 1 with A (idx,:) = []; what is done is to eliminate them and have a new Matrix of A without those rows.

Related Solutions

MATLAB: Output of k means clusters “idx”

idx will be a vector which has as many entries as there are rows in X.

The j'th entry, idx(j) tells you the cluster number that X(j,:) belongs to.

which_in_cluster = cell(k,1);
for j = 1 : k
    which_in_cluster{j} = find(idx == j);
end

Now which_in_cluster will be a cell array in which the j'th entry is a vector indicating which rows were part of the j'th cluster.

MATLAB: FetchNext idx always returning 1

The first output of fetchNext tells you which of the futures you passed in as an input has just completed. In your case, you are calling fetchNext(f(i)) - so you are always calling fetchNext with a single future, therefore the index is always 1.

You should pass all the futures into fetchNext, like this:

for i=1:3
    [idx, x]=fetchNext(f);
    disp(""+idx+" "+x);
end

Best Answer

Related Solutions

MATLAB: Output of k means clusters “idx”

MATLAB: FetchNext idx always returning 1

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