Help finding the min and max of a matrix without using min/max commands
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    Vinny
 on 9 Apr 2016
  
    
    
    
    
    Commented: ahmed yacine LARDJANE
 on 30 Nov 2020
            I'm having trouble trying to find the min and max of this matrix. So far I can only get it to display the min which is -12, but it doesn't display the max at all, it just shows the entire matrix when I try to display the max. Any help is appreciated, thank you.
 mat2=[-1 0 2;7 -4 12;4 8.2 11;-11 0 -12];
n=size(mat2);
max=mat2;
min=mat2;
for i=1:1:n(1);
    for j=1:1:n(2);
        if(mat2(i,j)>max);
            max=mat2(i,j);
        else(mat2(i,j)<min);
            min=mat2(i,j);
        end
    end
end
max 
min
1 Comment
  John D'Errico
      
      
 on 9 Apr 2016
				For your own sake, NEVER define a variable named min or max, or other existing functions.
If you do, then your next question will be the urgent one, WHY DOES MY CODE THAT TRIES TO USE THE MAX FUNCTION NOT WORK?
Accepted Answer
  Roger Stafford
      
      
 on 9 Apr 2016
        Change the two lines
   max=mat2;
   min=mat2;
to
   max = -inf;
   min = inf;
Note: It is a poor practice to use the terms 'max' and 'min' for variable names, since those are the names for matlab functions.
0 Comments
More Answers (1)
  Andrei Bobrov
      
      
 on 9 Apr 2016
        
      Edited: Andrei Bobrov
      
      
 on 9 Apr 2016
  
      mn = mat2(1);
mx = mat2(1);
for ii = 2:numel(mat2)
    if mat2(ii) < mn
        mn = mat2(ii);
        imn = ii;
    elseif mat2(ii) > mx
        mx = mat2(ii);
        imx = ii;
    end
end
without min and max :)
max1 = mat2(sum(bsxfun(@gt,mat2(:),mat2(:)'),2) == numel(mat2)-1);
min1 = mat2(sum(bsxfun(@lt,mat2(:),mat2(:)'),2) == numel(mat2)-1);
1 Comment
  ahmed yacine LARDJANE
 on 30 Nov 2020
				Hello, 
could you please answer me here? https://fr.mathworks.com/matlabcentral/answers/669058-finding-min-and-max-of-an-element-without-using-builtin-function/
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