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matlabsum

matlab sum function of NAN values

I have a matrix with potential NAN values. For example, A=[1,nan,1;nan,nan,nan]. I would like to have a summation by rows that looks like [2;nan], but could not find an easy and clean way of doing this. Any suggestions?

I am aware of the use of 'omitnan' option but it would only give me [2;0].

Solution

  • I know this might seem like over-engineering the solution, but here is a code excerpt that will work. You calculate the absolute sums of each of the rows using the 'omitnan' flag and then cross reference those rows where all elements are NaNs in the nan_check variable. Multiplying these together gives you the resultant matrix where all rows are summed up, and any rows that had all NaNs show up as NaN.

    sumMat = sum(A,2,'omitnan')
nan_check = double(~prod(isnan(A),2))
nan_check(nan_check==0) = NaN
sumMat.*nan_check