
Re: Merging multiple matrices
Posted:
May 9, 2013 10:37 AM


"Martijn van Sebille" <m.vansebille@deletethis.tudelft.nl> wrote in message news:kmgbic$eg$1@newscl01ah.mathworks.com... > "Bruno Luong" <b.luong@fogale.findmycountry> wrote in message > <kmg9vm$o98$1@newscl01ah.mathworks.com>... >> "Martijn van Sebille" wrote in message >> <kmg978$ljp$1@newscl01ah.mathworks.com>... >> > Dear, >> > >> > I am trying to efficiently merge multiple matrices, combining their >> > maximal values. For example: If A = [1 1 2; 1 2 1; 2 1 1] and B = [3 1 >> > 1; 1 3 1; 1 1 3], then their maximal values combined would be: C = [3 1 >> > 2; 1 3 1; 2 1 3]. >> >> C = max(A,B) >> >> If you have several, e.g., A1, A2, ...., A100, consider the for loop or >> using 3d array as temporary variable: >> >> C = { A1 , A2, ... A100 } >> C = max(cat(3,C{:}),[],3); >> >> % Bruno > > Thank you very much. The last suggestion works very well! > Do you also happen to know how to construct the C = { A1 , A2, ... A100 } > struct, without hardcoding the number of elements?
Ideally, avoid creating variables named A1, A2, etc. in the first place.
> At the moment I have 4 elements, so C = { A1, A2, A3, A4 }; However, the > number of elements depends on other variables in my script, which I would > like to be able to change. How could I program C so that is flexible like > that? > I hope it is clear what I mean.
Either create them as a 3D array in the first place like C in the code below, or store them in a cell array (and refer to them as such) as you go like D.
n = 10; C = zeros(7, 7, n); D = cell(1, n); for k = 1:10 C(:, :, k) = rand(7, 7); D{k} = randn(4, 5); end max(C, [], 3) max(cat(3, D{:}), [], 3)
 Steve Lord slord@mathworks.com To contact Technical Support use the Contact Us link on http://www.mathworks.com

