MATLAB Central Newsreader - Histogram

Histogram

Jonas — Sat, 07 Nov 2009 18:50:04 -0500

Does anybody have a better solution for the code below? The x- and edge-vectors has a size of 5000 elements in my problem, and the sum of k-vector is equal to the length of the x- and edge-vectors, the code allocates a lot of memory unnecessarily.

Similar problem
x = (1:1:11)';
u = [2 3.5 4 5 6 5 4 4 3 2 1]';
umin = min(u);
umax = max(u);
edge = linspace(umin,umax,numel(x))';
[k bin]=histc(u,edge);

u1 = zeros(length(k),max(k));
edge = flipud(edge);
for i=1:length(k)
u1(i,1:k(i))=edge(i);
end
[m,n] = size(u1);
for i=1:m
u2((i*n+1):((i+1)*n)) = u1(i,:);
end
ind1=find(u2==0);
u2(ind1)=[];
subplot(2,1,1); plot(x,u)
subplot(2,1,2); plot(x,u2)

Re: Histogram

Bruno Luong — Sun, 08 Nov 2009 09:22:02 -0500

Try this:

x = (1:1:11)';
u = [2 3.5 4 5 6 5 4 4 3 2 1]';
umin = min(u);
umax = max(u);
edge = linspace(umin,umax,numel(x))';

%
[k bin]=histc(u,edge);
u2=sort(edge(bin),'descend')'

% Bruno

Re: Histogram

Bruno Luong — Sun, 08 Nov 2009 09:35:18 -0500

sorry I forget to flip the edges

edge = flipud(edge);

Bruno