A dot in the place of a subscript indicates summation over that index (How to code this?)

Dear Community members,

I've been trying to code the following notation in Matlab but have not been successful... any idea?

T-of(i.) = SIGMA-of(j)T-of(ij)

From the article: We maintain the convention introduced earlier that a dot in the place of a subscript indicates summation over that index. Thus (above formula) will represent everything leaving i during the unit time interval should become apparent.

The article's title is "Quantifying sustainability: Resilience, efficiency and the return of information theory" if anyone is interested.

Many thanks and I look forward to your comments and suggestions.

Answer 1

[Wayne King]

That just means they're summing over the columns. You can do that with

X = randn(10,10);
sum(X,2)

% note each element in the above is
for ii = 1:size(X,1)
SumAlongCols(ii) = sum(X(ii,:));
end