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Unitary and symplectic (dual) polar graphs #18997
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Dependencies: #18972 |
comment:2
Is there any reason why you made this ticket depend on #18972? It seems easier to finalize, and apparently does not rely on anything from that other ticket. Nathann |
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comment:3
Replying to @nathanncohen:
this is merely to avoid merging troubles, as they are both changing |
comment:4
Okayokay. I am looking at generalized quadrangles at the moment. Seems that we will have to build some of them. Nathann |
comment:5
Replying to @nathanncohen:
we are already building
What remains is |
comment:6
Oh, really? Shouldn't they be incidence structures in their most natural form instead? I thought that it would make more sense to have a |
comment:7
Replying to @nathanncohen:
yes, sure, it's
well, they are a part of a more general construction, polar spaces. We can have |
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comment:9
actually, there already was |
Branch pushed to git repo; I updated commit sha1. Last 10 new commits:
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Branch pushed to git repo; I updated commit sha1. New commits:
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Branch pushed to git repo; I updated commit sha1. New commits:
|
Branch pushed to git repo; I updated commit sha1. New commits:
|
comment:15
for the life of me, I get
no matter how I try building the docs... |
comment:16
Does this help (maybe the changes for diff --git a/src/sage/graphs/generators/families.py b/src/sage/graphs/generators/families.py
index 0fadbbd..89777b0 100644
--- a/src/sage/graphs/generators/families.py
+++ b/src/sage/graphs/generators/families.py
@@ -2535,11 +2535,11 @@ def _polar_Graph(m, q, g, intersection_size=None):
TESTS::
- sage: from sage.graphs.generators.families import _polar_Graph
- sage: _polar_Graph(4, 4, libgap.GeneralUnitaryGroup(4, 2))
- Graph on 45 vertices
- sage: _polar_Graph(4, 4, libgap.GeneralUnitaryGroup(4, 2), intersection_size=1)
- Graph on 27 vertices
+ sage: from sage.graphs.generators.families import _polar_Graph
+ sage: _polar_Graph(4, 4, libgap.GeneralUnitaryGroup(4, 2))
+ Graph on 45 vertices
+ sage: _polar_Graph(4, 4, libgap.GeneralUnitaryGroup(4, 2), intersection_size=1)
+ Graph on 27 vertices
"""
from sage.libs.gap.libgap import libgap
from itertools import combinations
@@ -2675,17 +2675,17 @@ def SymplecticDualPolarGraph(m, q):
EXAMPLES::
- sage: G = graphs.SymplecticDualPolarGraph(6,2); G
- Symplectic Polar Graph O(6, 2): Graph on 135 vertices
- sage: G.is_distance_regular(parameters=True)
- ([14, 12, 8, None], [None, 1, 3, 7])
+ sage: G = graphs.SymplecticDualPolarGraph(6,2); G
+ Symplectic Polar Graph O(6, 2): Graph on 135 vertices
+ sage: G.is_distance_regular(parameters=True)
+ ([14, 12, 8, None], [None, 1, 3, 7])
TESTS::
- sage: G = graphs.SymplecticDualPolarGraph(6,3); G # long time
- Symplectic Polar Graph O(6, 3): Graph on 1120 vertices
- sage: G.is_distance_regular(parameters=True) # long time
- ([39, 36, 27, None], [None, 1, 4, 13])
+ sage: G = graphs.SymplecticDualPolarGraph(6,3); G # long time
+ Symplectic Polar Graph O(6, 3): Graph on 1120 vertices
+ sage: G.is_distance_regular(parameters=True) # long time
+ ([39, 36, 27, None], [None, 1, 4, 13])
"""
from sage.libs.gap.libgap import libgap
G = _polar_Graph(m, q, libgap.SymplecticGroup(m, q), If you feel like fixing some other minor docstring issues, you could make these changes, too: diff --git a/src/sage/graphs/generators/families.py b/src/sage/graphs/generators/families.py
index 0fadbbd..953b576 100644
--- a/src/sage/graphs/generators/families.py
+++ b/src/sage/graphs/generators/families.py
@@ -192,9 +192,9 @@ def BalancedTree(r, h):
TESTS:
- Normally we would only consider balanced trees whose root node
- has degree `r \geq 2`, but the construction degenerates
- gracefully::
+ Normally we would only consider balanced trees whose root node
+ has degree `r \geq 2`, but the construction degenerates
+ gracefully::
sage: graphs.BalancedTree(1, 10)
Balanced tree: Graph on 2 vertices
diff --git a/src/sage/graphs/generators/random.py b/src/sage/graphs/generators/random.py
index 01f9c13..246250d 100644
--- a/src/sage/graphs/generators/random.py
+++ b/src/sage/graphs/generators/random.py
@@ -749,7 +749,7 @@ def RandomToleranceGraph(n):
sage: g.clique_number() == g.chromatic_number()
True
- TEST:
+ TEST::
sage: g = graphs.RandomToleranceGraph(-2)
Traceback (most recent call last):
diff --git a/src/sage/graphs/generators/smallgraphs.py b/src/sage/graphs/generators/smallgraphs.py
index 39ca04e..27e1124 100644
--- a/src/sage/graphs/generators/smallgraphs.py
+++ b/src/sage/graphs/generators/smallgraphs.py
@@ -1810,7 +1810,7 @@ def ChvatalGraph():
2
4
- TEST:
+ TEST::
sage: import networkx
sage: G = graphs.ChvatalGraph()
@@ -2647,7 +2647,7 @@ def FruchtGraph():
'KhCKM?_EGK?L'
sage: (graphs.FruchtGraph()).show() # long time
- TEST:
+ TEST::
sage: import networkx
sage: G = graphs.FruchtGraph()
@@ -2896,7 +2896,7 @@ def HeawoodGraph():
'MhEGHC@AI?_PC@_G_'
sage: (graphs.HeawoodGraph()).show() # long time
- TEST:
+ TEST::
sage: import networkx
sage: G = graphs.HeawoodGraph()
@@ -3363,7 +3363,7 @@ def KrackhardtKiteGraph():
sage: g = graphs.KrackhardtKiteGraph()
sage: g.show() # long time
- TEST:
+ TEST::
sage: import networkx
sage: G = graphs.KrackhardtKiteGraph()
diff --git a/src/sage/graphs/strongly_regular_db.pyx b/src/sage/graphs/strongly_regular_db.pyx
index 44a6640..f28248c 100644
--- a/src/sage/graphs/strongly_regular_db.pyx
+++ b/src/sage/graphs/strongly_regular_db.pyx
@@ -1518,7 +1518,7 @@ def strongly_regular_graph(int v,int k,int l,int mu=-1,bint existence=False):
...
RuntimeError: Sage cannot figure out if a (1394,175,0,25)-strongly regular graph exists.
- Test the Claw bound (see 3.D of [vLintBrouwer84]_):
+ Test the Claw bound (see 3.D of [vLintBrouwer84]_)::
sage: graphs.strongly_regular_graph(2058,242,91,20,existence=True)
False You could also change "TEST:" to "TESTS:" throughout, but I don't really care much about that. |
Branch pushed to git repo; I updated commit sha1. New commits:
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Branch pushed to git repo; I updated commit sha1. New commits:
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comment:19
Helloooooooo Dima, Here is a 'first-pass' review:
Nathann |
Author: Dima Pasechnik |
Reviewer: Nathann Cohen |
comment:21
Replying to @nathanncohen:
oops, it's a bug...
this is |
comment:24
Helloooooooo Dima,
Thank you very much for this code. Nathann |
comment:25
Replying to @nathanncohen:
it's always better to have 2 implementations... I'll rearrange as you ask.
yep, how about renaming
How about I'll move them into examples and mark them # not tested (long time)?
all these I'd rather include this as a reference. Perhaps it's more meaningful to create a separate module, say polar_families.py, We could also extend the wikipedia page https://en.wikipedia.org/wiki/Distance-regular_graph and have docs there...
this would be even more meaningful with a new module. |
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comment:27
I'd rather do the reorganisation elsewhere. E.g. to make the list of dual polar graphs complete, one should add orthogonal dual polar graphs. |
comment:28
Hello,
+1
Works for me.
+1
+1. Though I beware of wikipedia now. I have experienced how hard it is to fight the whims of those who are "in charge" of some pages...
+1
Reorganization can indeed wait, but must not forget to address the "SymplecticDualPolarGraph" vs "SymplecticGraph" issue. Nathann |
Changed branch from u/dimpase/unitary to |
implement the classical unitary (reps. symplectic) ordinary and dual polar graphs
U(n,q)
(resp.Sp(2d,q)
), seehttp://www.win.tue.nl/~aeb/graphs/srghub.html for the ordinary ones, and [BCN89] for the dual ones (for these of diameter bigger than 2).
As well, recognise the corresponding SRGs in the DB.
Depends on #18972
CC: @nathanncohen
Component: graph theory
Author: Dima Pasechnik
Branch/Commit:
ee9c5d6
Reviewer: Nathann Cohen
Issue created by migration from https://trac.sagemath.org/ticket/18997
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