Adding each row to previous row in a vector-Not Cumulative
2 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Hi , I've looked everywhere to find the solution for this but I couldn't find the answer. Here 's the problem. How to add each row in a vector with just the previous row? For example here is the process on this vector: A=[2 1 7 9 4] and the answer should be this vector: C=[3 8 16 13]
Thanks in advance.
0 Commenti
Risposta accettata
Sukuchha
il 20 Lug 2011
A=[2 1 7 9 4]; B = A(1:end-1)+diff(cumsum(A));
1 Commento
Jan
il 20 Lug 2011
diff(cumsum(A)) ?! An expensive method to get: A(2:end). But in addition there is the danger of rounding errors, e.g. diff(cumsum([1e16, 1, 5])) is [0, 4] ! Therefore I strongly recommend not to use this.
Più risposte (3)
Jan
il 20 Lug 2011
Easier and faster:
B = A(1:end-1) + A(2:end)
2 Commenti
Sukuchha
il 21 Lug 2011
Jan, your method is better ! i feel like stupid now ! I need to remember always solve problems in a simplier way !
Jan
il 21 Lug 2011
@Sukuchha: Often a direct translation of the human language is helpful. You've formulated your algorithm very clear already: "add each row in a vector with just the previous row". So you did solve the biggest part of the problem already. Most of the questions in this forum are much less clear.
Paulo Silva
il 20 Lug 2011
C=arrayfun(@(x)plus(A(x),A(x-1)),2:numel(A))
or with a for loop
C=zeros(1,size(A,2)-1);
for x=2:size(A,2)
C(x-1)=A(x)+A(x-1);
end
C
0 Commenti
Vedere anche
Categorie
Scopri di più su Subplots in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!