cumulative sum in a loop

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Joseph Lee
Joseph Lee 2017-10-20
编辑： Andrei Bobrov 2017-10-23
c = 1;
while c <= 5
i = 1;
while i <= 10,
z = rand(1, 10);
Z(c, i) = z(i) % how to get this to add the previous c=1 if this is c=2 loop to be cumulative sum
end
end
example:
C = 1 Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 Z10
C = 2 Z1 + Z1' Z2+Z2' Z3 + Z3' ( Z' is a new random number)
C = 3 Z1 + Z1'+Z1''
  2 个评论
Rik
Rik 2017-10-20
Two questions: Why are you using while loops, and why don't you generate a larger random matrix, so you can reference previous values.
Is this a homework question? If it is, could you post the original question as well? And have you looked at how you might be able to tweak a call to cumsum?
Joseph Lee
Joseph Lee 2017-10-23
how do i generate a larger cumulative matrix? this is just a short summary of a part of code for project, for each loop theres calculations involving related equations that uses the random number. I need to generate random number for each loop and to save it at the end, then use it for the next set of loop for cumulative sum.

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Andrei Bobrov
Andrei Bobrov 2017-10-23
编辑：Andrei Bobrov 2017-10-23
Z = rand(10,1,10);
Z_add = randi(5,2,10);
out = cumsum([Z;Z_add]);
with for - loop
m = 5;
Z = randi(20,1,10);
n = size(Z,2);
Z_out = [Z;zeros(m-1,n)];
for ii = 2:m
Z_out(ii,:) = Z_out(ii-1,:) + randi(5,1,n);
end

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