sum every 5 rows of a column, Is the part of code right

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I am trying to sum every 5 rows of a column, Is my part of code right
instdec = (instdec_t+instdec_d)/2;
startdec1 = (instdec >= 0.25*overalldec);
startdec2=zeros(npts,1);
while decpt==1
for j = 2:npts-4
startdec2(j) = sum(startdec1(j:j+4));
if startdec2(j)== 5
decpt=j-1;
break
end
end
I keep getting wrong answers, the second row becomes 2, and everything else is zeros
I would appreciate any support since I am very new to matlab
  2 Comments
Jan
Jan on 17 Jun 2013
I've applied a more readable indentation. Now it is obvious that an end is missing.
The purpose of your code is not clearly explained. All we have is the code you have shown here. Then it is impossible to guess, if it satisfies your needs. Please add a detailed description of the aim of the program - by editing the original question, not as comment and not as answer. Thanks.
Tom
Tom on 17 Jun 2013
can you provide some example data to test with?

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Accepted Answer

Andrei Bobrov
Andrei Bobrov on 17 Jun 2013
Edited: Andrei Bobrov on 17 Jun 2013
startdec2 = sum(reshape([startdec1;zeros(mod(-numel(startdec1),5),1)],5,[])).';
ADD
startdec1 = rand(42,1) < .7;
b = conv(startdec1,ones(5,1),'valid');
decpt = find(b == 5,1,'first')-1;
  5 Comments
Hamaza24
Hamaza24 on 18 Jun 2013
Thanks I really appreciate it. I worked it out :)

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More Answers (1)

Hamaza24
Hamaza24 on 17 Jun 2013
Hi Jan and tom.
the purpose is to check if the numbers on every row exceed a certain value for a 5 successive rows.
so, the methodology I used is that if the condition of exceeding that certain number happens then generate 1, otherwise 0.
to check the of every five successive rows meet the condition, I want to sum every 5 rows and when the sum is 5 then I know that location and get its original value.
I can't really provide data tom. sorry for that and thanks for your help.

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