MATLAB: How to generalize 2 dimensions into n dimensions with a for loop

for loopMATLAB

Hi,
In 2D, I have a script like this:
bx = [min(x(1,:)) : ( (max(x(1,:)) - min(x(1,:))) /20 ) : max(x(1,:))];
by = [min(x(2,:)) : ( (max(x(2,:)) - min(x(2,:))) /20 ) : max(x(2,:))];
But here's the problem: x can have more than 2 rows. As a result, I want to have b's like:
bz = [min(x(3,:)) : ( (max(x(3,:)) - min(x(3,:))) /20 ) : max(x(3,:))];
ba = [min(x(4,:)) .....
....
....
So I need a for loop. I tried to do it like:
[M N] = size(x);
for s=1:1:M-1
      b(s,:) = [min(x(s,:)) : (max(x(s,:))-min(x(s,:)))/20 : max(x(s,:))];
end
But I get the "Subscripted assignment dimension mismatch." error. I tried to ask this in http://www.mathworks.com/matlabcentral/answers/84556-how-can-i-create-a-specific-matrix-in-a-for-loop but since I couldn't clarify myself clearly, I didn't get the correct answer, the suggestion with doing this with linspace instead of colon didn't seem to work.
Edit: Another idea that comes to mind is this:
b = min(x(1,end)) : ((max(x(1,end))-min(x(1,end)))/20) : max(x(1,end));
but this doesn't generate a b matrix strangely. In the variable editor b seems like a 1×0 matrix with nothing inside if I do this statement instead.
The problem is not with the for loop, even if I don't do a for loop, and just write
   b(1,:) = [min(x(1,:)) : ((max(x(1,:))-min(x(1,:)))/20) : max(x(1,:))];
I still get the same dimension mismatch error. So the problem has to do with the b(1,:) colon in this statement.

Best Answer

i1=min(x,[],2);i2=max(x,[],2);       % the limits for conciseness
n=repmat(20,size(x,1),1);            % the number of points wanted
b= cell2mat(arrayfun(@linspace,i1,i2,n,'uniformoutput',0));
Original problem is that apparently linspace() is not able to handle a vector input -- I didn't look into why too much (like any).
The straightforward addressing of
b=i1:(i2-i1)/(n-1):i2;
doesn't work since only the first row is evaluated by colon().
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