Info

이 질문은 마감되었습니다. 편집하거나 답변을 올리려면 질문을 다시 여십시오.

What is the problem in these code?

조회 수: 2 (최근 30일)
Selin Soguksu
Selin Soguksu 2012년 12월 19일
마감: MATLAB Answer Bot 2021년 8월 20일
Hello friends, I have a code like this:
for x=1:50
Nrows=size(orj_matr,1)
new_matr=randperm(Nrows)
new_matr=new_matr(1:50)
a(:,:,x)=orj_matr(new_matr,:)
end
When I wrote this codes to MATLAB, I have 50 different (50 rows-10 columns) matrices. Like this:
a(:,:,1) , a(:,:,2), a(:,:3), …………a(:,:,50)
And I want to calculate f1 and f2 for these 50 different matrices. When I wrote like this there was an error saying “Indexing must appear last in an index expression”.
f1=sum(a(:,:,x) (:,1:2:end),2);
f2=sum(a(:,:,x) (:,2:2:end),2);
What is the mistake in these codes? Please help me...
  댓글 수: 1
Jan
Jan 2012년 12월 19일
편집: Jan 2012년 12월 19일
It would be useful if you explain, what the the expression "a(:,:,x) (:,1:2:end)" should do. As long as it is no valid Matlab syntax, a suggestion for improvement requires guessing what you want to achieve. And an answer based on guesses can be worse than no answer.

답변 (2개)

Jürgen
Jürgen 2012년 12월 19일
편집: Jürgen 2012년 12월 19일
Hi,
sum(a(:,:,x) (:,1:2:end),2); is not correct , I think What do you want to do there? '(:,1:2:end)' is referring to the index and it put at the right place regards,J
  댓글 수: 3
José-Luis
José-Luis 2012년 12월 19일
I would recommend you read up on indexing.
a(:,:,x) (:,1:2:end)
is not a valid expression. I am guessing that what you want is something along the lines
squeeze(sum(a(:,1:2:end,:),2))
Also, please edit your code to make it more readable. That might attract more answers.
Jürgen
Jürgen 2012년 12월 19일
편집: Jan 2012년 12월 19일
to sum all even columns:sum(A(:,2:2:end)) for odd columns: sum(A(:,1:2:end))

Selin Soguksu
Selin Soguksu 2012년 12월 19일
Thanks all of you for the answers and comments. I saw my mistake and correct my codes. Now it works good. I know my codes are not clear enough, because I am very new with MATLAB. And also sometimes I can't tell you what I want because of my poor English.
  댓글 수: 3
José-Luis
José-Luis 2012년 12월 19일
And the mistake was?
Selin Soguksu
Selin Soguksu 2012년 12월 20일
When I assign a(:,:,x) to a new variable, and use this variable to the entire of the code, there was no problem.

태그

제품

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by