Index exceeds matrix dimensions.
조회 수: 1 (최근 30일)
이전 댓글 표시
I am trying to create a covariance matrix for a class assignment. I loaded two columns of data x and y, each has 136 rows. I then entered "raw_data=[data_x(:,4),data_y(:,4)];cov_matrix=cov(raw_data)" based on my professors instructions and I get the error message Index exceeds matrix dimensions. I'm thinking this means I need to adjust the (:,4) part but I don't really know what it means so I don't know what to change it to.
댓글 수: 1
Austin
2015년 12월 21일
Is there a fourth column in your data vectors? (:,4) can be read "the entry in all rows for column 4". If they are just nx1 then changing the 4 to 1 should work. Unless the cov() function works differently than I am assuming.
답변 (1개)
Chad Greene
2015년 12월 21일
What is the size of data_x? You can check this by
size(data_x)
When you call data_x(:,4) it's trying to access all 136 rows of the fourth column in data_x. I suspect data_x may not have 4 columns. If data_x and data_y only have one column each, computing the covariance matrix will be easy:
cov_matrix=cov([data_x data_y])
댓글 수: 0
참고 항목
카테고리
Help Center 및 File Exchange에서 Matrices and Arrays에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!