MATLAB: How to quickly find the first non-zero element without iterations in all columns in a sparse matrix

first non-zero elementsparse matrix

Hi, All,
I have a big sparse matrix A. I want to find out the first non-zero element in all columns from the top. Here is my code:
reorderCol = [];
for jCol = 1 : length(A(1,:))
eee = find(A(:,jCol),1,'first');
reorderCol = [reorderCol eee];
end
For example, I have matrix A = [0 0 0;0 5 0;0 0 1;0 0 0;-1 0 -4]. My code gives the following result:
reorderCol = [5 2 3];
I am wondering if it is possible to obtain reorderCol without iterations. Thanks a lot.
Benson

Best Answer

  • [~,result]=max(logical(A),[],1);