save while runing loop

This is my full code:

aa=rand(2,2,2)

aa(1,1,1)=5;

aa(2,1,1)=8;

aa(1,2,1)=3;

aa(2,2,1)=3;

aa(1,1,2)=7;

aa(2,1,2)=8; aa(1,2,2)=3;

aa(2,2,2)=3;

dimention_aa=size(aa); aareshaped=reshape(aa,[2,4])

ii=rand(3,1);

ii(1,1)=8;

ii(2,1)=3;

ii(3,1)=7;

 for( l=(ii(1):ii(end)))
 ind_reshaped=find(aareshaped==l)
      [R1, C1, S1]=ind2sub(dimention_aa,find(aareshaped==l)
      k=[R1, C1, S1]
      x1=k(:,1)
      y1=k(:,2)
      z1=k(:,3)
      newMatrix = zeros(dimention_aa)
      for j = 1 : size(k, 1)
         newMatrix( x1(j) , y1(j) ,z1(j)) = 1
      end
     % roi_mat(l,:)=x;
end   
%%%%%%%%%%%%%%%%%%%%%%%%%%%%Basically the k matrix(that has lines correspondent to xyz positions) is genereated by

[R1, C1, S1]=ind2sub(dimention_aa,find(aareshaped==l)

k=[R1, C1, S1]

And l is a vector with diferent numbers. How do I do the same procedure to go through every element of "l"; and then save the "newMatrix with the corresponding index? The code I wrote above, doesn't work quite well.. Regards

[Image Analyst]

And this is the tutorial: http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

Answer 1

[Geoff Hayes]

Hi André - a couple of things: the above doesn't run because of the missing bracket at the end of the second line in

 ind_reshaped=find(aareshaped==l)
 [R1, C1, S1]=ind2sub(dimention_aa,find(aareshaped==l)

Since the first line above is unused, just remove it and add the closing bracket (and semi-colon) to the end of the second line

 [R1, C1, S1]=ind2sub(dimention_aa,find(aareshaped==l));

The code is iterating over the contents of the ii vector but the body of the for loop never gets evaluated because the code iterates as

 for( l=(ii(1):ii(end)))

which fails on the first attempt since the first element (of ii) is 8 and the second element is 3: 8>3 so the for loop ends before it begins. Instead, the code could iterate over the contents of the ii vector and just assign l as the first line in the body of the for loop

 for a=1:length(ii)
     l = ii(a);
     % etc.

Now you want to save the newMatrix at each iteration of the outer for loop. There are several ways you can do this, but since you want to save the index as well, the easiest way is to just use a cell array

 data = {};  % this array will contain the matrix and index pairs
 atEl = 1;   % this is the next index into the above array

 for a=1:length(ii)
     l = ii(a);
     % etc.

Then after the inner for loop has been completed, just save newMatrix and the index (is this k or l?) as

 for j = 1 : size(k, 1)
   newMatrix( x1(j) , y1(j) ,z1(j)) = 1
 end

 data{atEl}.mtx = newMatrix;
 data(atEl}.idx = k;  % or l or ??
 atEl = atEl + 1;     % increment to the next index

You may also want to consider adding semi-colons to the end of each assignment statement in your code so that the result of that is not written to the console on each iteration.

You may also want to add some error checking code to handle the case where find(aareshaped==l) returns an empty matrix.

Hope that the above helps!

[André Sousa]

thaks a lot for the clarifying answer!

[Geoff Hayes]

My pleasure!

[bashar halleem]

Realy it is good Answer