Error raised when non-multi(di)graph receive multiple edges as input

[nathanncohen]

sage: Graph([(0,1),(0,1)],multiedges=False)
Traceback (most recent call last):
...
ValueError: Non-multigraph input dict has multiple edges (0,1)
sage: DiGraph([(0,1),(0,1)],multiedges=False)
Traceback (most recent call last):
...
NameError: global name 'choice' is not defined

The first message is much clearer :-P

Nathann

Component: graph theory

Keywords: digraph, multiedges, error

Author: Vincent Delecroix

Branch/Commit: f6102dd

Reviewer: Nathann Cohen

Issue created by migration from https://trac.sagemath.org/ticket/16215

[nathanncohen]

New commits:

7f50072

trac #16215: A missing import

[nathanncohen]

Branch: u/ncohen/16215

[nathanncohen]

Commit: 7f50072

[videlec]

comment:3

Could you instead replace

choice([v for v in data[u] if data[u].count(v) > 1])

with

(v for v in data[u] if data[u].count(v) > 1).next()

or anything similar. The function choice involves some randomness that is useless here.

[videlec]

Reviewer: Vincent Delecroix

[nathanncohen]

comment:4

But it's funny... And it has been there from the start, and there is the same in Graph !

Nathann

[videlec]

comment:5

It is funny, but it was wrong and nobody noticed... so the simplest, the best. Especially in the code of a complicated constructor (~600 lines for the one in Graph). And as you mentioned, It would be better to remove the one in Graph as well ;-P

Vincent

[nathanncohen]

comment:6

For me the simplest is to add the missing line. If you want to solve it differently, add a commit. There is nothing tricky involved, you do not need me to write it.

Nathann

[videlec]

Changed branch from u/ncohen/16215 to u/vdelecroix/16215

[videlec]

Changed commit from 7f50072 to f6102dd

[videlec]

comment:7

We now have

sage: Graph([(0,1),(0,1)], multiedges=False)
Traceback (most recent call last):
...
ValueError: Non-multigraph got several edges (0,1)
sage: DiGraph([(0,1),(0,1)], multiedges=False)
Traceback (most recent call last):
...
ValueError: Non-multidigraph got several edges (0,1)

Needs review.

---

New commits:

f6102dd

Error when multiple edges are sent to a Non-multi(di)graph

[videlec]

Changed reviewer from Vincent Delecroix to none

[videlec]

Changed keywords from none to digraph, multiedges, error

[videlec]

Changed author from Nathann Cohen to Vincent Delecroix

[nathanncohen]

comment:8

All tests pass, good to go !

Nathann

[videlec]

comment:9

Thanks !

[vbraun]

comment:10

Reviewer name

[videlec]

Reviewer: Nathann Cohen

[videlec]

comment:11

Replying to @vbraun:

Reviewer name

Sorry. Here it is.

[vbraun]

Changed branch from u/vdelecroix/16215 to f6102dd