Assign a label to a point of a matrix in if statement

Hi, I'm trying to assign a label (based on a category from a table) to each element of a 10*10 matrix in an if statement such that if the value is smaller or larger from a threshold, the corrosponding element gets assigned a certain category label with the index of the element so that it can be known which element it is . For example:

Kappa=rand(10,10);
KappaLong=rand(10,10);
KappaShort=rand(10,10);
for i=1:10
    for j=1:10
        if ((abs(Kappa(i,j)))/(abs(KappaLong(i,j)))<1) && ((abs(Kappa(i,j)))/(abs(KappaShort(i,j)))<1)
            Kappa(i,j)='Point is stable: Category 1 is assigned' %to show which element of the matrix is stable
        elseif ((abs(Kappa(i,j)))/(abs(KappaLong(i,j)))>1) && ((abs(Kappa(i,j)))/(abs(KappaShort(i,j)))>1)
            Kappa(i,j)='Point is unstable'
% (the code should continue after the elseif)
                 if abs(Kappalong)>abs(KappaShort)
                    ModKappa=abs(KappaLong)
                 else ModKappa=abs(KappaShort)
         end
     end
  end
end

I know the code above is not complete or correct, just wanted to provide an example about what I mean. Thank you in advance.

[Bob Thompson]

It seems like you have a good idea of what you want to do. What do you need us to help with? Are you getting an error (please post it in its entirety)? Or are you trying to clean up your code to make it faster? Something else?

[MarshallSc]

Thanks for your reply Bob. Well, when I want to execute the code, I'll receive the following error in the line Kappa_j(i,j)='Point is stable: Category 1 is assigned' :

Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-39.

I was wondering whether I'm writing this part incorrectly.

[Stephen23]

Note that storing lots of scalar numeric data in a cell array makes processing that data much slower and more complex. You should probably store the "status" string in a separate string array, and keep the numeric data in a numeric array.

Answer 1

[the cyclist]

By default, Kappa_j is going to be a numeric array, and there cannot accept character input. Instead, you could define it as a cell array:

Kappa_j = cell(2,2); % Preallocate the cell array, but smaller to illustrate
Kappa_j{1,1} = 'Point is stable: Category 1 is assigned'

Kappa_j = 2×2 cell array
    {'Point is stable: Category 1 is assigned'}    {0×0 double}
    {0×0 double                               }    {0×0 double}

Notice the use of curly brackets to access the "inside" of the cell.

[MarshallSc]

Thanks a lot sir, I was thinking that about the same method too. Thanks again.