Difference between revisions of "Perm inv"
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(Created page with "{{Function |name=perm_inv |desc=Computes the inverse of a permutation |upd=November 28, 2012 |v=1.00 |helper=1}} <tt>'''perm_inv'''</tt> is a function th...") |
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|name=perm_inv | |name=perm_inv | ||
|desc=Computes the inverse of a permutation | |desc=Computes the inverse of a permutation | ||
| + | |rel=[[perm_sign]] | ||
|upd=November 28, 2012 | |upd=November 28, 2012 | ||
|v=1.00 | |v=1.00 | ||
Revision as of 17:14, 21 January 2013
| perm_inv | |
| Computes the inverse of a permutation | |
| Other toolboxes required | none |
|---|---|
| Related functions | perm_sign |
| 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.
Syntax
- PI = perm_inv(PERM)
Argument descriptions
- PERM: A vector containing a permutation of the integers 1, 2, ..., n.
Examples
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