How do you circshift progressive rows an increasing amount?

If I have a matrix:

[nan nan nan nan nan]

[ 1a nan nan nan nan]

[ 1b 2b nan nan nan]

[ 1c 2c 3c nan nan]

[ 1d 2d 3d 4d nan]

I want to change it to this:

[ 1a 2b 3c 4d nan]

[ 1b 2c 3d nan nan]

[ 1c 2d nan nan nan]

[ 1d nan nan nan nan]

[nan nan nan nan nan]

I tried:

for K = 1:length(A)

A = circshift(A(:,K),K);

Thank you.

[David Hyatt]

I got this to work:

done = []

for M = 1:5

stemp = circshift(A(:,M),-M,1);

done = [done stemp];

end

------------

Originally I didn't have semicolons. Oops.

[Rik]

Yes, that is indeed very slow. See my answer for a faster solution.

[David Hyatt]

It was going slow because of missing semicolons. Oops. I'm not sure how to turn your solution in to code to try. If you would like to provide a sample I will try it out. The code I made does the 400x400 matrix in about a second for reference.

[Rik]

I have edited my answer to include the edit I meant. Dynamically growing an array is a bad idea, as mlint is warning you. You should make it a habit of resolving every mlint warning. Either suppress them (right-click and select suppress warning on this line), or change the code.

Answer 1

[Rik]

You need to index a column in A in your output as well.

for K = 1:size(A,2)
   A(:,K) = circshift(A(:,K),K);
end

If you want to move every NaN to the bottom, you can also use the sort function.

[David Hyatt]

Thank you for the help and explanation!