SHAKE

Randomize a matrix along one dimension (ver 4 .1 may 2008)

Description

SHAKE - Randomize a matrix along a specific dimension

Y = SHAKE(X) randomizes the order of the elements in each column of the 2D matrix. For N-D matrices it randomizes along the first dimension.
 
SHAKE(X,DIM) randomizes along the dimension DIM.

[Y, I, J] = SHAKE(...) return index matrices I and J so that Y = X(I) and X = Y(J).
 
Example:
  A = [1 2 3 ; 4 5 6 ; 7 8 9 ; 10 11 12] ; % see <slm> on the FEX ...
  Dim = 2 ;
  [B, ID] = shake(A,Dim) % ->, e.g.
  % 3 2 1
  % 6 4 5
  % 7 8 9
  % 11 10 12%
 
See also RAND, SORT, RANDPERM
and RANDSWAP on the File Exchange

Latest version: 4.1 (may 2008)

Acknowledgements

This file inspired Randswap and Permute A Grouped Vector.

• MATLAB release: MATLAB 6.5 (R13)

[Jos (author)]

New version: 3.0 (oct 2006)

[Gregory Anderson]

Simple? Yes, but I couldn't figure out how to do it on my own, and it does exactly what it's supposed to do, so thanks, Jos.

[Jos vdG]

Which tests? Note that <shake> simply uses the built-in matlab <rand> function ...

[Peter He]

Tests show that the quality of randomization is not good. Cannot be trusted in serious simulations.

[John D'Errico]

Its not shaky at all. Certainly not its documentation, which is as clear as even I could ask for.