How to set elements of a matrix to 0 from one index to the remaining of the row ?

Hi, I'm working on a large sparse matrix. I'm wondering if there is a fast way to set elements of a matrix to 0 from one given index (dependent on the row) to the remaining of the row ?

For each row, I have a linear index and I would like to set all the elements from this index to the end of the row to 0. Obviously you can achieve that with a for loop (see the code) but for efficiency reasons, I was wondering if there were a faster solution for that! Any idea?

X % sparse matrix of size m x n
Indexes % Linear Indexes of size m x 1
size_X=size(X); 
[~,Column_Index]=ind2sub(size_X,Indexes); % get the column number of each Indexes

for i=1:length(Indexes)
    X(i,Column_Index(i):end)=0;
end

For example, if

 X =[
  1     3     -1     1
  22     2     2     2
  3     3     3     3]

and

Indexes =[
     7
     2
     9]

X should become:

1 3 0 0

0 0 0 0

3 3 0 0

Answer 1

[Matt J]

[I,J,S]=find(X);
keep=(J<Column_Index(I));

X=sparse(I(keep), J(keep), S(keep) ,m,n);