Writing nanmedian into an array.

Hello everyone. I use nanmedian to calculate the median values excluding nan of a 3d Array and then store the elements in a 2d Array as follows.

 for i=1:size(tempBeforeDelam,1)

    for j=1:size(tempBeforeDelam,2)

            if all( abs( diff([ squeeze(tempBeforeDelam(i,j,:)); tempBeforeDelam(i,j,1) ]) ) < 1)  

                beforeDelam(i,j)= nanmedian(tempBeforeDelam(i,j,1:5),3);

                %beforeDelam(i,j)= median(tempBeforeDelam(i,j,1:5),3,'omitnan');

            end   
    end
end

the Problem here with nanmedian or median with omitnan flag is that it is not omitting the Nan only while writing into the Array.

For example,consider row 1279069 and column 1 along my 3rd Dimension,

tempBeforeDelam(1279069,1,1) = 13.4567

tempBeforeDelam(1279069,1,1) = NaN

tempBeforeDelam(1279069,1,1) = 13.3564

tempBeforeDelam(1279069,1,1) = 13.4657

tempBeforeDelam(1279069,1,1) = 13.4346

nanmedian of above 5 elements is 0 in my Output Array. i.e even if there is one Nan Output is Zero. But if call the same row in the command window and find the nanmedian i get the right answer. Can someone tell me why I get a Problem while writing it into the Array and how I can solve it??

I have also attached a Picture to Show the Problem I have.

Answer 1

[Guillaume]

I strongly suspect that your problem is with the if condition rather than nanmedian. if there is a NaN in your matrix, then diff is going to return a NaN, which is never smaller than 1. Therefore your condition will not be true, and the body of the if (the assignment to beforeDelam) is never executed.

[Snehalatha]

Hey thanks. i think you might be right. I will try this and let you know. I didn't realise this point at all. thanks again.