How do I gain indices of max values in 2D matrix?
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For a 16 x 12 matrix I should sort it in descending order to gain the max values (like 10 in total). After that, I should find what was the indices of those max values before sorting .
I tried several times with sort and find. But it doesn't give me correct result.
2 Comments
  Azzi Abdelmalek
      
      
 on 8 Apr 2014
				
      Edited: Azzi Abdelmalek
      
      
 on 8 Apr 2014
  
			You have two columns, you have to precise how you want to sort them
  Azzi Abdelmalek
      
      
 on 8 Apr 2014
				You have a 16x12 matrix, there are several ways to sort your matrix, by rows or by columns? you have to give more details, or just show the result for a short example, if
A=[1 2;3  4;0 1;4 5 ;100  20;2 2;0 7]
What should be the result?
Answers (3)
  Walter Roberson
      
      
 on 8 Apr 2014
        [sorted, idx] = sort(YourMatrix, 'rows', 'descend');
tenmax = idx(1:10);
2 Comments
  Walter Roberson
      
      
 on 8 Apr 2014
				[sorted, idx] = sortrows(YourMatrix, -(1:size(YourMatrix,2)));
tenmax = idx(1:10);
this will give you the indices of the original rows that got sorted to the corresponding row position.
  Gautam
    
 on 10 Apr 2014
        The answer above gives you the indices of before sorting. Try this example.
    A = [1 4; 6 2; 4 2; 7 3]
    [sortedMat,sortedIndex] = sort(A,'descend')
The sortedIndex matrix gives indices of the original rows (Note here that each column is sorted independently)
0 Comments
  Jos (10584)
      
      
 on 10 Apr 2014
        Why sort first?
A = [1 4; 6 2; 4 2; 7 3]
[maxValues, RowIndex] = max(A,[],1)
LinearIndex = sub2ind(size(A),RowIndex, 1:size(A,2))
sortedA = sort(A,1,'descend')
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