A = [ 1 2 3 NaN NaN NaN 7 8 ]';
B = [ 1 1 1 1 NaN NaN 1 1 ]';
Check which rows are ok...
isOK=isfinite(A)|isfinite(B);
C=sum([A,B],2,'omitnan');
C(~isOK)=nan
Could encapsulate in a little function to make clean at top level...
mysum=sumeither(A,B)
function s=sumeither(A,B)
% returns sum of finite elements of vectors A,B
assert(isvector(A)&&isvector(B),'Both inputs must be vectors')
assert(numel(A)==numel(B),'Both inputs must be same length')
M=[A(:) B(:)]; % catenate to array, be sure are columns
s=sum(M,2,'omitnan'); % add up the finite elements
s(all(isnan(M),2))=nan; % mark the missing rows
end
