arrayfun doesn't work with rmoutliers

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Tom K.
Tom K. on 5 Jan 2022
Edited: Tom K. on 5 Jan 2022
Goal
Remove outliers along dimension d of a 3D matrix using arrayfun and rmoutliers (or superior alternatives).
Minimal Working Example
Take the following matrix:
A = [0 2 0 0 0; 0 0 0 4 0; 3 0 0 3 0];
A(:,:,2) = A
A =
A(:,:,1) = 0 2 0 0 0 0 0 0 4 0 3 0 0 3 0 A(:,:,2) = 0 2 0 0 0 0 0 0 4 0 3 0 0 3 0
Since each 1D array along dimension d will have a different number of outliers, the output of arrayfun will have to be a cell array (by specifying "UniformOutput" = false). Calling rmoutliers through arrayfun returns the original matrix with the outliers (undesired behaviour):
arrayfun(@rmoutliers,A,"UniformOutput",false)
ans = 3×5×2 cell array
ans(:,:,1) = {[0]} {[2]} {[0]} {[0]} {[0]} {[0]} {[0]} {[0]} {[4]} {[0]} {[3]} {[0]} {[0]} {[3]} {[0]} ans(:,:,2) = {[0]} {[2]} {[0]} {[0]} {[0]} {[0]} {[0]} {[0]} {[4]} {[0]} {[3]} {[0]} {[0]} {[3]} {[0]}
The function works as expected when called on each row by itself:
rmoutliers(A(1,:,1)) % removes the 2
ans = 1×4
0 0 0 0
rmoutliers(A(3,:,1)) % removes both 3's
ans = 1×3
0 0 0
Hopefully I'm missing something trivial.

Accepted Answer

Voss
Voss on 5 Jan 2022
A = [0 2 0 0 0; 0 0 0 4 0; 3 0 0 3 0];
A(:,:,2) = A
A =
A(:,:,1) = 0 2 0 0 0 0 0 0 4 0 3 0 0 3 0 A(:,:,2) = 0 2 0 0 0 0 0 0 4 0 3 0 0 3 0
C = num2cell(A,2)
C = 3×1×2 cell array
C(:,:,1) = {[0 2 0 0 0]} {[0 0 0 4 0]} {[3 0 0 3 0]} C(:,:,2) = {[0 2 0 0 0]} {[0 0 0 4 0]} {[3 0 0 3 0]}
cellfun(@rmoutliers,C,"UniformOutput",false)
ans = 3×1×2 cell array
ans(:,:,1) = {[0 0 0 0]} {[0 0 0 0]} {[ 0 0 0]} ans(:,:,2) = {[0 0 0 0]} {[0 0 0 0]} {[ 0 0 0]}

More Answers (1)

Mike Croucher
Mike Croucher on 5 Jan 2022
arrayfun operates on every element of the array. So
arrayfun(@rmoutliers,A,"UniformOutput",false)
is like doing
rmoutliers(0)
rmoutliers(0)
rmoutliers(3)
etc
  1 Comment
Tom K.
Tom K. on 5 Jan 2022
Edited: Tom K. on 5 Jan 2022
Hi Mike,
I was able to produce the desired results using @Benjamin's solution.
Thanks!

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