Array notation instead of iterative loop for difference equation

1 view (last 30 days)
Hi, I have somehow a difference equation and wanted to improve the speed of my code and calculate it directly through arrays instead of an iterative loop.
I have a container that is continuously filled. It is emptied at certain times.
I would like to have the mass at each time step of the container.
With an iterative loop I calculated it:
% Dummy values for the incomming mass
m_new = randi(50,288,1);
% Time slots to empty the container
m_empty = false(size(m_new));
m_empty([60,60+96, 60+2*96]) = true;
% Use the mass of the previous time step unless the container has been emptied
contents_remaining = xor(true, m_empty);
% Initializing my array for the loop
mm = zeros(size(m_new));
% Initialize my array with a start value
mm(1) = 300;
% For each time step, calculate the content from the previous time step and the newly added mass.
for i = 1:size(m_new,1)-1
mm(i+1) = mm(i) * contents_remaining(i) + m_new(i);
end
Is it possible to perform this calculation without a for loop?
Unfortunately, I have not come up with a satisfactory result and hope you can help me to avoid the for loop.
  6 Comments
Stephen23
Stephen23 on 14 Nov 2023
"Is it possible to perform this calculation without a for loop?"
Why?
Torsten
Torsten on 14 Nov 2023
Edited: Torsten on 14 Nov 2023
Ok, that means I wasn't on the wrong track, but there is no better solution to the problem.
Yes, recursions are hard (or even impossible ?) to vectorize.

Sign in to comment.

Answers (0)

Categories

Find more on Creating and Concatenating Matrices in Help Center and File Exchange

Products


Release

R2023a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!