[Haskell-cafe] finding the right mathematical model

John Lato jwlato at gmail.com
Wed Jul 7 09:27:59 EDT 2010

If you ignore the identity mappings (which all technically create
trivial loops), these mappings would form a directed acyclic graph
(DAG).  I would look at some of the graph libraries, e.g. fgl, to see
if they have anything appropriate.


> From: G?nther Schmidt <gue.schmidt at web.de>
> Hi list,
> the problem I have stems from the app I had developed. What my app does
> is to split the money a hospital receives for a case to the departments
> involved in a fair way.
> An additional requirement however was to allow the users of the app to
> re-map any revenue shares credited to certain departments to other
> departments. Such cases are sometimes due to politics within the
> hospital and also have more legitimate reasons, like saying the
> radiology should not receive shares for surgical procedures but those
> shares should be redirected to the "General surgery" department.
> The feature is already implemented, but I'm not pleased with it,
> especially since I did not develop a mathematical model for it.
> Details:
> It boils down to model mappings, or rather what sort of data structure
> would be suited for this kind of thing.
> Dept A is "mapped" to itself
>     A -> A
> Dept B is mapped to Dept C
>     B -> C
> Dept C is mapped to Dept C
>     C -> C
> Dept D is mapped to Dept A
>     D -> A
> It should not be possible to construct looping mappings, ie.
>   1. A -> B
>   2. B -> C
>   3. C -> A
> ......
> What sort of model would be suitable to describe this, some sort of matrix?
> Günther

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