Index exceeds matrix dimensions

I've got two matrices, Fluorescence <3840x15> and H <96x15>. I want to divide 40 Fluorescence values in each column by a value in the corresponding H column. Running the code as is results in a matrix J, but with just the first 40 rows of Fluorescence divided by the first row of H, instead of the <3840x15> matrix I wanted to end up with.

J = [];
K = [];
k = 1;
n = 1;
for i = 1:(r/40)
   for j = 1:c
    I = Fluorescence(k:(k+39),j) / H(n,j);
    J = cat(2,J,I);
   end
   k = k + 40;
   n = n + 1;
   K = cat(1,K,J);
  end

[Ryan]

fixed this by clearing J at the end of each iteration of i.

K = cat(1,K,J);
J = [];
end

Answer 1

[Matt Fig]

I think you mean this:

F = randi(100,3840,15);  % Random 3840-by-15
H = randi(100,96,15);    % Random 96-by-15;
J = F./expand(H,[40,1]);

Note that the EXPAND function is found on this page: EXPAND

Another way to do it without using the EXPAND function (with the same F and H as above):

J = zeros(3840,1);
J(1:40:end) = 1;
J = F./H(cumsum(J),:);

Answer 2

[Image Analyst]

Do you have the Image Processing Toolbox? If you do, it's just two lines:

% Generate sample data.
Fluorescence = rand(3840, 15);
H = rand(96,15);

% Resize H to be the same size as Fluorescence.
H_matchingSize = imresize(H, size(Fluorescence), 'nearest');
% Divide them.
output = Fluorescence ./ H_matchingSize;

Or even one line:

output = Fluorescence ./ imresize(H, size(Fluorescence), 'nearest');

[Richard Brown]

or with a little more convoluted syntax, you can do it without the image processing toolbox

H_matching_size = interp1(1:96, H, reshape(repmat(1:96, 40, 1), 96*40, 1));

which is basically what imresize is doing

Answer 3

[Azzi Abdelmalek]

out=Fluorescence (1:40,:)./H(1:40,:)