[Distutils] name of the dependency problem

[Wes Turner]

IIRC, Conda (BSD License) takes a SAT solving (e.g. Sudoku) approach:
http://continuum.io/blog/new-advances-in-conda

(such as installing "pycosat"  (MIT License) when I install conda).

Some links to the source:
* https://github.com/conda/conda/blob/master/conda/logic.py
* https://github.com/conda/conda/blob/master/tests/test_logic.py'
* https://github.com/conda/conda/blob/master/conda/resolve.py
* https://github.com/conda/conda/blob/master/tests/test_resolve.py
... https://github.com/conda/conda/blob/master/conda/toposort.py

On Apr 15, 2015 6:14 AM, "Robin Becker" <robin at reportlab.com> wrote:

> After again finding that pip doesn't have a correct dependency resolution
> solution a colleage and I discussed the nature of the problem. We examined
> the script capture of our install and it seems as though when presented with
>
>
> level 0 A
>   A level 1  1.4<= C
>
>
> level 0 B
>   B level 1  1.6<= C <1.7
>
> pip manages to download version 1.8 of C(Django) using A's requirement,
> but never even warns us that the B requirement of C was violated. Surely
> even in the absence of a resolution pip could raise a warning at the end.
>
> Anyhow after some discussion I realize I don't even know the name of the
> problem that pip should try to solve, is there some tree / graph problem
> that corresponds? Searching on dependency seems to lead to topological
> sorts of one kind or another, but here we seem to have nodes with discrete
> values attached so in the above example we might have (assuming only
> singleton A & B)
>
> R --> A
> R --> B
>
> A --> C-1.4
> A --> C-1.6
> A --> C-1.6.11
> A --> C-1.7
> A --> C-1.8
>
> B --> C-1.6
> B --> C-1.6.11
>
> so looking at C equivalent nodes seems to allow a solution set. Are there
> any real problem descriptions / solutions to this kind of problem?
> --
> Robin Becker
> _______________________________________________
> Distutils-SIG maillist  -  Distutils-SIG at python.org
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>
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