Center n-th Dimension of Array
Fiber-center across the levels of the specified mode. Can input 2-way, 3-way, and 4-way arrays, or input a list containing array elements.
ncenter(X, mode = 1)
X |
Array (2-way, 3-way, or 4-way) or a list containing array elements. |
mode |
Mode to center across. |
With X a matrix (I-by-J) there are two options:
mode=1: |
x[i,j] - mean(x[,j]) |
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mode=2: |
x[i,j] - mean(x[i,]) |
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With X a 3-way array (I-by-J-by-K) there are three options:
mode=1: |
x[i,j,k] - mean(x[,j,k]) |
|
mode=2: |
x[i,j,k] - mean(x[i,,k]) |
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mode=3: |
x[i,j,k] - mean(x[i,j,]) |
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With X a 4-way array (I-by-J-by-K-by-L) there are four options:
mode=1: |
x[i,j,k,l] - mean(x[,j,k,l]) |
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mode=2: |
x[i,j,k,l] - mean(x[i,,k,l]) |
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mode=3: |
x[i,j,k,l] - mean(x[i,j,,l]) |
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mode=4: |
x[i,j,k,l] - mean(x[i,j,k,]) |
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Returns centered version of X.
When entering a list with array elements, each element must be an array (2-way, 3-way, or 4-way) that contains the specified mode to center across.
Nathaniel E. Helwig <helwig@umn.edu>
########## EXAMPLE 1 ########## X <- matrix(rnorm(2000),100,20) Xc <- ncenter(X) # center across rows sum(colSums(Xc)) Xc <- ncenter(Xc,mode=2) # recenter across columns sum(colSums(Xc)) sum(rowSums(Xc)) ########## EXAMPLE 2 ########## X <- array(rnorm(20000),dim=c(100,20,10)) Xc <- ncenter(X,mode=2) # center across columns sum(rowSums(Xc)) ########## EXAMPLE 3 ########## X <- array(rnorm(100000),dim=c(100,20,10,5)) Xc <- ncenter(X,mode=4) # center across 4-th mode sum(rowSums(Xc)) ########## EXAMPLE 4 ########## X <- replicate(5,array(rnorm(20000),dim=c(100,20,10)),simplify=FALSE) Xc <- ncenter(X) sum(colSums(Xc[[1]]))
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