Perm inv

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Computes the inverse of a permutation

Other toolboxes required none
Related functions perm_sign
Function category Helper functions
This is a helper function that only exists to aid other functions in QETLAB. If you are an end-user of QETLAB, you likely will never have a reason to use this function.

perm_inv is a function that computes the inverse of a permutation.


  • PI = perm_inv(PERM)

Argument descriptions

  • PERM: A vector containing a permutation of the integers 1, 2, ..., n.


Small examples

The identity permutation is its own inverse:

>> perm_inv(1:4)

ans =

     1     2     3     4

To compute the inverse of the permutation on this MathWorld page, we can use the following line of code:

>> perm_inv([3,8,5,10,9,4,6,1,7,2])

ans =

     8    10     1     6     3     7     9     2     5     4

Source code

Click here to view this function's source code on github.