How to sum individual elements MATLAB -


suppose have row matrix [a1 a2 a3 a4 .. an] , wish achieve each of following in matlab

    1) 1+a1     2) 1+a1+a2     3) 1+a1+a2+a3     4) 1+a1+a2+a3+a4 ....      1+a1+a2+...+an

how shall them?

this purpose of cumsum function. if a vector containing elements [a1 a2 a3 .. an] then

b = cumsum([1 a]);

contains terms searching for. possibility is

b = 1 + cumsum(a);

edit

if don't want use built-in function cumsum, simpler way go for loop:

% consider preallocation speed b = nan(numel(a),1);     % assign first element b(1) = 1 + a(1);  % loop = 2:numel(a)   b(i) = b(i-1) + a(i); end

or, without preallocation:

b = 1 + a(1); = 2:numel(a)   b(end+1) = b(end) + a(i); end

best,


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