How to subtract Mean from Matrix along columns

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JFz
JFz 2017-11-16
编辑： John D'Errico 2017-11-16
Hi,
In subtraction, there is an example of subtract mean from matrix: A - mean(A) and it works well. But I have a matrix A of 15X1000, and I want to subtract the mean mean(A, 2) along the 1000 columns, how to do that? Thanks Jennifer

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JFz
JFz 2017-11-16
With the above help, found that bsxfun works for versions before 2017a:
bsxfun(@minus, A, mean(A, 2))

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KL
KL 2017-11-16
编辑：KL 2017-11-16
Just the same way, A-A_mean. Here's an example with 5 columns,
>>A = reshape(1:25,5,5) %dummydata
A =
1 6 11 16 21
2 7 12 17 22
3 8 13 18 23
4 9 14 19 24
5 10 15 20 25
>>A_mean = mean(A,2)
A_mean =
11
12
13
14
15
>>A = A-A_mean
A =
-10 -5 0 5 10
-10 -5 0 5 10
-10 -5 0 5 10
-10 -5 0 5 10
-10 -5 0 5 10
EDIT (thanks John)
and for older versions,
A = bsxfun(@minus,A,A_mean)
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JFz
JFz 2017-11-16
I tried the above but got this error: Error using - Matrix dimensions must agree.
I am using 2016a. I will have to change a lot of code to upgrade to 2017a successfully. Thanks, let me look at repmat and bsxfun.
JFz
JFz 2017-11-16
OK. bsxfun works! bsxfun(@minus, A, mean(A, 2))

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JFz
JFz 2017-11-16
Thanks to KL and John! Have a nice day!

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