Opened 4 years ago
Closed 4 years ago
#18948 closed enhancement (fixed)
Strongly Regular Graphs database
Reported by:  ncohen  Owned by:  

Priority:  major  Milestone:  sage6.8 
Component:  graph theory  Keywords:  
Cc:  dimpase  Merged in:  
Authors:  Nathann Cohen  Reviewers:  Dima Pasechnik 
Report Upstream:  N/A  Work issues:  
Branch:  d1d25a0 (Commits)  Commit:  d1d25a03964f92c590449bebd359b21e7feaf349 
Dependencies:  #18934  Stopgaps: 
Description (last modified by )
This ticket implements a new module names strongly_regular_db
that lets us build one example of strongly regular graph, given four integer parametes (v,k,lambda,mu).
It uses Andries Brouwer's database to return more meaningful nonexistence results, and help us find which constructions are missing from the database.
With a bit of luck (and time, and work) it would be great if we could reproduce all SRG that are known to exist!
The module has a simple structure:
has a simple structure:
 A
seems_feasible(v,k,l,mu)
function that performs the basic artihmetic checks to figure out if(v,k,l,mu)
is realizable. The 'apparently_feasible_parameters(n)` returns the lists of all parameters that pass these tests for v<n. When n=1301, the set of parameters it returns is precisely those that appear on your database (this is checked in the code).
 Several functions (is_paley, is_johnson, ...) test if a given set of parameters (v,k,l,mu) can be realized with a graph of the corresponding family (a Paley graph, a Johnson graph, ...). If they can, they return the parameters of that graph so that it can be built easily.
 The main function
strongly_regular_graph
can be called in two ways:
strongly_regular_graph(v,k,l,mu,existence=True)
answers True if such a graph is known to exists, False if it is known to be infeasible, and Unknown otherwise.
strongly_regular_graph(v,k,l,mu)
attempts to build and return the requested graph, and returns a meaningful exception if it cannot.
This branch also updates the package 'graphs', which now ships the database in json format.
http://www.steinertriples.fr/ncohen/tmp/graphs20150724.tar.bz2
Nathann
Attachments (1)
Change History (75)
comment:1 Changed 4 years ago by
 Description modified (diff)
 Status changed from new to needs_review
comment:2 Changed 4 years ago by
 Branch set to u/ncohen/18948
 Commit set to f599ffee2d99ba7a18f14667b596f921c3b7a995
comment:3 Changed 4 years ago by
 Commit changed from f599ffee2d99ba7a18f14667b596f921c3b7a995 to a0173e2789e7a8f79c88a77d753b48788f183e65
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
a0173e2  trac #18948: Strongly Regular Graphs database

comment:4 Changed 4 years ago by
 Commit changed from a0173e2789e7a8f79c88a77d753b48788f183e65 to 4adcf950cd34c28460383468b17b59c695633f01
Branch pushed to git repo; I updated commit sha1. New commits:
4adcf95  trac #18948: Two missing graphs

comment:5 followup: ↓ 6 Changed 4 years ago by
I think you do not need to edit module_list.py file anymore when there is no dependencies. See #15410.
comment:6 in reply to: ↑ 5 Changed 4 years ago by
I think you do not need to edit module_list.py file anymore when there is no dependencies. See #15410.
I removed it and all doctests break because of an import problem. As I do not mind much either way personally, I leave it like that.
Nathann
comment:7 followup: ↓ 8 Changed 4 years ago by
this comment landed on the wrong ticket (#18960), sorry:
Test if a Paley graph is `(v,k,\lambda,\mu)`strongly regular.
Huh? Do you mean
Test whether a `(v,k,\lambda,\mu)`strongly regular graph is Paley.
All the similar docstrings have the same problem. Namely, one tests that a (v,k,l,m)srg is BlahBlah
, not the other way around...
comment:8 in reply to: ↑ 7 Changed 4 years ago by
this comment landed on the wrong ticket (#18960), sorry:
Test if a Paley graph is `(v,k,\lambda,\mu)`strongly regular.Huh? Do you mean
Test whether a `(v,k,\lambda,\mu)`strongly regular graph is Paley.
To me your phrasing also sounds incorrect, as it seems to test whether "every (v,k,l,mu)strongly regular graph is a Paley graph".
What about replacing 'a' by 'some'?
Test if some Paley graph is (v,k,l,mu)strongly regular
Nathann
comment:9 Changed 4 years ago by
 Commit changed from 4adcf950cd34c28460383468b17b59c695633f01 to a9280c9ae07f2703e7d004d463a77d8e6482025f
comment:10 followup: ↓ 11 Changed 4 years ago by
Do you really want to keep mu as a required by functions parameter? I would rather get rid of it, for it is a simple computation to find mu given the 1st three parameters.
comment:11 in reply to: ↑ 10 Changed 4 years ago by
Do you really want to keep mu as a required by functions parameter? I would rather get rid of it, for it is a simple computation to find mu given the 1st three parameters.
I prefer to keep it, for it belongs to the definition of strongly regular graphs. I don't see anything wrong it making it optional: we can replace 'None' by the computed value if necessary.
Nathann
comment:12 Changed 4 years ago by
 Commit changed from a9280c9ae07f2703e7d004d463a77d8e6482025f to 0ed84411d7d2eb896530a961255739939e3a7609
Branch pushed to git repo; I updated commit sha1. New commits:
0ed8441  trac #18948: guess mu

comment:13 followup: ↓ 14 Changed 4 years ago by
 Commit changed from 0ed84411d7d2eb896530a961255739939e3a7609 to cf8f2dad1cd90ff5aaa0cec15a25f87c64289719
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
cf8f2da  trac #18948: guess mu

comment:14 in reply to: ↑ 13 ; followup: ↓ 15 Changed 4 years ago by
Replying to git:
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
cf8f2da trac #18948: guess mu
How about functions like is_paley()
? They also do not need mu
...
By the way, what is the point of doing return (lambda q : PaleyGraph(q),v)
instead of
return PaleyGraph(v)
?
comment:15 in reply to: ↑ 14 Changed 4 years ago by
How about functions like
is_paley()
? They also do not needmu
...
If you think that this feature would be useful, I have nothing against your adding it in another ticket. I do not see the point, as those functions are not even meant to be called directly by users, who can do so with 'strongly_regular_graph' (which can automatically guess 'mu' if needed).
By the way, what is the point of doing
return (lambda q : PaleyGraph(q),v)
instead ofreturn PaleyGraph(v)
?
That's in order to be able to tell if the construction *can* be done without doing it (which can take quite some time). Very useful to know which entries Sage can build to compare it to the list of those that are known to exist. I used a design similar to the one used in sage.combinat.designs.orthogonal_arrays_find_construction
, where many functions exist to *guess* the parameters of some constructions (exactly like it is done here). With these design, knowing if something can be built and getting the data to build it is done in the same operation. There are two advantages:
1) No need of a 'exists=True' optional keyword when you call the function 2) No 'if exists' everywhere in the code's function, to return 'True' instead of returning the graph 3) If you want to test the existence, THEN build the graph, you do not call the function twice with different parameters (which would not use the function's cache, and so you compute the decomposition twice).
Admittedly, the functions of the design code are computationally much more expensive than those.
Nathann
comment:16 Changed 4 years ago by
it seems that
cdef eigenvalues(int v,int k,int l,int mu)
only returns correct results for the nonPaley (nonconference) case (i.e. the case where the eigenvalues are not integer).
This should be documented, at least.
comment:17 Changed 4 years ago by
 Commit changed from cf8f2dad1cd90ff5aaa0cec15a25f87c64289719 to aed4022eb9ea74be3cb3acab1ff9b1570b01c6e8
Branch pushed to git repo; I updated commit sha1. New commits:
aed4022  trac #18948: DOcstring

comment:18 Changed 4 years ago by
 Commit changed from aed4022eb9ea74be3cb3acab1ff9b1570b01c6e8 to 4f51703c4e63909516d4711714a5429cfd4f5050
Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:
4f51703  trac #18948: DOcstring

comment:19 followup: ↓ 20 Changed 4 years ago by
there are easy to implement necessary conditions on parameters which don't seem to be there, e.g. Krein conditions, absolute bound, etc; see 9.1.8 in http://www.win.tue.nl/~aeb/2WF02/spectra.pdf
I don't mind them to be added in a followup ticket, but it has to be done, I think.
comment:20 in reply to: ↑ 19 ; followup: ↓ 25 Changed 4 years ago by
I don't mind them to be added in a followup ticket, but it has to be done, I think.
I know, I already have plans for that. I planned to do it after #18960.
Nathann
comment:21 Changed 4 years ago by
 Status changed from needs_review to positive_review
comment:22 Changed 4 years ago by
Thanks !
comment:23 Changed 4 years ago by
 Commit changed from 4f51703c4e63909516d4711714a5429cfd4f5050 to a75774fa9f6168b4f0e34c6cdd93496f7283b179
 Status changed from positive_review to needs_review
Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:
a75774f  trac #18948: take into account the BIBD from #18934

comment:24 Changed 4 years ago by
 Status changed from needs_review to positive_review
comment:25 in reply to: ↑ 20 Changed 4 years ago by
comment:27 Changed 4 years ago by
 Reviewers set to Dima Pasechnik
comment:28 Changed 4 years ago by
 Status changed from needs_work to positive_review
comment:29 followup: ↓ 30 Changed 4 years ago by
these graphs, O(2d1,q), are available, but not known to your DB:
sage: o=graphs.OrthogonalPolarGraph(5,4) sage: o.is_strongly_regular(parameters=True) (85, 20, 3, 5) sage: graphs.strongly_regular_graph(85, 20, 3, 5)  RuntimeError Traceback (most recent call last) <ipythoninput29152b95dceef4> in <module>() > 1 graphs.strongly_regular_graph(Integer(85), Integer(20), Integer(3), Integer(5)) /home/dima/software/sage/src/sage/graphs/strongly_regular_db.pyx in sage.graphs.strongly_regular_db.strongly_regular_graph (build/cythonized/sage/graphs/strongly_regular_db.c:12463)() 1061 if existence: 1062 return True > 1063 raise RuntimeError(("Andries Brouwer's database claims that such a "+ 1064 "({},{},{},{})strongly regular graph exists, but "+ 1065 "Sage does not know how to build it. If *you* do, "+ RuntimeError: Andries Brouwer's database claims that such a (85,20,3,5)strongly regular graph exists, but Sage does not know how to build it. If *you* do, please get in touch with us on sagedevel! Comments: O(5,4) Sp(4,4); GQ(4,4) sage:
comment:30 in reply to: ↑ 29 Changed 4 years ago by
these graphs, O(2d1,q), are available, but not known to your DB:
Done at #18988
sage: graphs.strongly_regular_graph(85, 20, 3, 5) Orthogonal Polar Graph O(5, 4): Graph on 85 vertices
Nathann
comment:31 Changed 4 years ago by
 Commit changed from a75774fa9f6168b4f0e34c6cdd93496f7283b179 to d1d25a03964f92c590449bebd359b21e7feaf349
 Status changed from positive_review to needs_review
Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:
a0cac66  trac #18934: new BIBD: (91,7,1), (66,6,1), (76,6,1), (96,6,1)

e46b058  trac #18934: New (v,6,1)BIBD with v=201

a04a2fb  trac #18934: Broken doctests

11e9f1f  trac #18934: Last one > (126,6,1)BIBD

796bcde  trac #18934: Merged with 6.8.rc1

6ed1abf  trac #18934: Fixed credits

62ce12c  trac #18934: Merged with beta0

f4f5566  trac #18948: Merge with updated #18934

d1d25a0  trac #18948: Broken doctest

comment:32 Changed 4 years ago by
 Dependencies set to #18934
 Status changed from needs_review to positive_review
comment:33 followup: ↓ 35 Changed 4 years ago by
 Status changed from positive_review to needs_work
With #18988, #18960, and #18948:
sage t long src/sage/graphs/strongly_regular_db.pyx ********************************************************************** File "src/sage/graphs/strongly_regular_db.pyx", line 1209, in sage.graphs.strongly_regular_db._check_database Failed example: _check_database() # long time Expected: Sage cannot build a (45 22 10 11 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Mathon78">Mathon</a>; 2graph* ... In Andries Brouwer's database:  448 impossible entries  2950 undecided entries  1140 realizable entries (Sage misses 298 of them) Got: Sage cannot build a (45 22 10 11 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Mathon78">Mathon</a>; 2graph* Sage cannot build a (96 19 2 4 ) that exists. Comment from Brouwer's database: Haemers(4); <a href="srgtabrefs.html#Muzychuk07">Muzychuk S6</a> (n=4,d=2); <a href="srgtabrefs.html#Brouwer_et_al03">BrouwerKoolenKlin</a>; <a href="srgtabrefs.html#Golemac_et_al06">Golemac et al.</a> Sage cannot build a (96 20 4 4 ) that exists. Comment from Brouwer's database: GQ(5,3); <a href="srgtabrefs.html#Brouwer_et_al03">BrouwerKoolenKlin</a>; <a href="srgtabrefs.html#Golemac_et_al06">Golemac et al.</a> Sage cannot build a (96 75 58 60 ) that exists. Comment from Brouwer's database: Sage cannot build a (96 76 60 60 ) that exists. Comment from Brouwer's database: Sage cannot build a (100 44 18 20 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#JorgensenKlin03">JrgensenKlin</a>; RSHCD<sup></sup>; 2graph Sage cannot build a (100 45 20 20 ) that exists. Comment from Brouwer's database: OA(10,5)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (100 54 28 30 ) that exists. Comment from Brouwer's database: OA(10,6)?; 2graph Sage cannot build a (100 55 30 30 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (105 32 4 12 ) that exists. Comment from Brouwer's database: Aut L(3,4) on flags (rk 4)  <a href="srgtabrefs.html#GoethalsSeidel70">Goethals & Seidel</a>, unique by <a href="srgtabrefs.html#Coolsaet05">Coolsaet</a> Sage cannot build a (105 72 51 45 ) that exists. Comment from Brouwer's database: Sage cannot build a (120 42 8 18 ) that exists. Comment from Brouwer's database: L(3,4) on Baer subplanes (rk 5), unique by <a href="srgtabrefs.html#DegraerCoolsaet08">Degraer & Coolsaet</a> Sage cannot build a (120 51 18 24 ) that exists. Comment from Brouwer's database: NO<sup></sup>(5,4); 2graph Sage cannot build a (120 56 28 24 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (120 63 30 36 ) that exists. Comment from Brouwer's database: dist. 2 in J(10,3)  Mathon; NO<sup>+</sup>(8,2); GoethalsSeidel(3,7); pg(7,8,4)  <a href="srgtabrefs.html#Cohen81">Cohen</a>; see also <a href="srgtabrefs.html#DeClerckDelanote00">De Clerck & Delanote</a>; 2graph Sage cannot build a (120 68 40 36 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (120 77 52 44 ) that exists. Comment from Brouwer's database: Witt: intersection3 graph of a 2(21,7,12) design with block intersections 1, 3 Sage cannot build a (122 55 24 25 ) that exists. Comment from Brouwer's database: switch OA(11,6)+*; switch skewhad<sup>2</sup>+*; 2graph Sage cannot build a (122 66 35 36 ) that exists. Comment from Brouwer's database: S(2,6,61)?; 2graph Sage cannot build a (125 28 3 7 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Godsil92">Godsil</a>(q=5,r=3); GQ(4,6) Sage cannot build a (125 52 15 26 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Godsil92">Godsil</a>(q=5,r=2); pg(4,12,2)?; 2graph* Sage cannot build a (125 72 45 36 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (125 96 74 72 ) that exists. Comment from Brouwer's database: Sage cannot build a (126 25 8 4 ) that exists. Comment from Brouwer's database: dist. 1 or 4 in J(9,4)  Mathon, Buekenhout & Hubaut Sage cannot build a (126 45 12 18 ) that exists. Comment from Brouwer's database: NO<sup></sup>(6,3); pg(5,8,2)? Sage cannot build a (126 50 13 24 ) that exists. Comment from Brouwer's database: Goethals  unique by <a href="srgtabrefs.html#CoolsaetDegraer08">Coolsaet & Degraer</a>; 2graph Sage cannot build a (126 60 33 24 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (126 65 28 39 ) that exists. Comment from Brouwer's database: pg(5,12,3)?; Taylor 2graph for U<sub>3</sub>(5) Sage cannot build a (126 75 48 39 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (126 80 52 48 ) that exists. Comment from Brouwer's database: Sage cannot build a (126 100 78 84 ) that exists. Comment from Brouwer's database: Sage cannot build a (136 60 24 28 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (136 63 30 28 ) that exists. Comment from Brouwer's database: NO<sup></sup>(8,2); 2graph Sage cannot build a (136 72 36 40 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (136 75 42 40 ) that exists. Comment from Brouwer's database: NO<sup>+</sup>(5,4); 2graph Sage cannot build a (144 39 6 12 ) that exists. Comment from Brouwer's database: L<sub>3</sub>(3) (rk 8) Sage cannot build a (144 65 28 30 ) that exists. Comment from Brouwer's database: RSHCD<sup></sup>; 2graph Sage cannot build a (144 78 42 42 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (144 104 76 72 ) that exists. Comment from Brouwer's database: Sage cannot build a (165 36 3 9 ) that exists. Comment from Brouwer's database: U(5,2) polar graph; GQ(4,8) Sage cannot build a (165 128 100 96 ) that exists. Comment from Brouwer's database: Sage cannot build a (170 78 35 36 ) that exists. Comment from Brouwer's database: switch OA(13,7)+*; 2graph Sage cannot build a (170 91 48 49 ) that exists. Comment from Brouwer's database: S(2,7,85)?; 2graph Sage cannot build a (175 30 5 5 ) that exists. Comment from Brouwer's database: GQ(6,4) Sage cannot build a (175 72 20 36 ) that exists. Comment from Brouwer's database: edges of HoffmanSingleton graph  Haemers; pg(4,17,2)  <a href="srgtabrefs.html#Haemers81">Haemers</a>; 2graph* Sage cannot build a (175 102 65 51 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (175 144 118 120 ) that exists. Comment from Brouwer's database: Sage cannot build a (176 40 12 8 ) that exists. Comment from Brouwer's database: pg(10,3,2) does not exist (Absolute bound for line graph) Sage cannot build a (176 49 12 14 ) that exists. Comment from Brouwer's database: Higman symmetric 2design; pg(7,6,2)? Sage cannot build a (176 70 18 34 ) that exists. Comment from Brouwer's database: S(4,7,23)S(3,6,22)  M<sub>22</sub>/Alt(7); unique by Coolsaet & Degraer; 2graph Sage cannot build a (176 85 48 34 ) that exists. Comment from Brouwer's database: Haemers; 2graph Sage cannot build a (176 90 38 54 ) that exists. Comment from Brouwer's database: pg(5,17,3)?; 2graph Sage cannot build a (176 105 68 54 ) that exists. Comment from Brouwer's database: Witt 3(22,7,4): intersection3 graph of a quasisymmetric 2(22,7,16) design with intersection numbers 1, 3; 2graph Sage cannot build a (176 126 90 90 ) that exists. Comment from Brouwer's database: Sage cannot build a (176 135 102 108 ) that exists. Comment from Brouwer's database: NU(5,2) Sage cannot build a (196 90 40 42 ) that exists. Comment from Brouwer's database: RSHCD<sup></sup>; 2graph Sage cannot build a (196 91 42 42 ) that exists. Comment from Brouwer's database: OA(14,7)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (196 104 54 56 ) that exists. Comment from Brouwer's database: OA(14,8)?; 2graph Sage cannot build a (196 105 56 56 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (209 100 45 50 ) that exists. Comment from Brouwer's database: pg(10,9,5)?; 2graph* Sage cannot build a (209 108 57 54 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (210 99 48 45 ) that exists. Comment from Brouwer's database: Sym(7)  Klin; 2graph Sage cannot build a (210 110 55 60 ) that exists. Comment from Brouwer's database: pg(11,9,6)?; 2graph Sage cannot build a (220 84 38 28 ) that exists. Comment from Brouwer's database: Tonchev: intersection3 graph of a 2(45,9,8) design with block intersections 1, 3 Sage cannot build a (220 135 78 90 ) that exists. Comment from Brouwer's database: pg(9,14,6)? Sage cannot build a (225 98 43 42 ) that exists. Comment from Brouwer's database: OA(15,7)?; Pasechnik(15) Sage cannot build a (225 112 55 56 ) that exists. Comment from Brouwer's database: skewhad$^2$; OA(15,8)?; 2graph* Sage cannot build a (225 126 69 72 ) that exists. Comment from Brouwer's database: OA(15,9)? Sage cannot build a (226 105 48 49 ) that exists. Comment from Brouwer's database: switch skewhad<sup>2</sup>+*; 2graph Sage cannot build a (226 120 63 64 ) that exists. Comment from Brouwer's database: S(2,8,113)?; 2graph Sage cannot build a (243 22 1 2 ) that exists. Comment from Brouwer's database: 3<sup>5</sup>.2.M<sub>11</sub> (rk 3)  BerlekampvanLintSeidel; Golay code: projective ternary [11,5] code with weights 6, 9 Sage cannot build a (243 110 37 60 ) that exists. Comment from Brouwer's database: 3<sup>5</sup>.2.M<sub>11</sub> (rk 3)  Delsarte; projective ternary [55,5] code with weights 36, 45 Sage cannot build a (243 132 81 60 ) that exists. Comment from Brouwer's database: Sage cannot build a (243 220 199 200 ) that exists. Comment from Brouwer's database: Sage cannot build a (253 112 36 60 ) that exists. Comment from Brouwer's database: S(4,7,23)  M<sub>23</sub> Sage cannot build a (253 140 87 65 ) that exists. Comment from Brouwer's database: Witt 4(23,7,1): intersection3 graph of a 2(23,7,21) design with block intersections 1, 3 Sage cannot build a (256 68 12 20 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Brouwer85">Brouwer</a>(q=2,d=4,e=2,); projective binary [68,8] code with weights 32, 40 Sage cannot build a (256 85 24 30 ) that exists. Comment from Brouwer's database: vanLintSchrijver(1); CK  CY1: projective binary [85,8] code with weights 40, 48 Sage cannot build a (256 102 38 42 ) that exists. Comment from Brouwer's database: 2<sup>8</sup>.L<sub>2</sub>(17) (rk 3)  Liebeck; vanLintSchrijver(2); CK  CY1: projective 4ary [34,4] code with weights 24, 28 Sage cannot build a (256 153 92 90 ) that exists. Comment from Brouwer's database: vanLintSchrijver(3) Sage cannot build a (256 170 114 110 ) that exists. Comment from Brouwer's database: vanLintSchrijver(2) Sage cannot build a (256 187 138 132 ) that exists. Comment from Brouwer's database: Sage cannot build a (276 135 78 54 ) that exists. Comment from Brouwer's database: ConwayGoethals&Seidel; 2graph Sage cannot build a (276 140 58 84 ) that exists. Comment from Brouwer's database: pg(5,27,3)?; 2graph Sage cannot build a (279 128 52 64 ) that exists. Comment from Brouwer's database: pg(8,15,4)?; 2graph* Sage cannot build a (279 150 85 75 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (280 36 8 4 ) that exists. Comment from Brouwer's database: J<sub>2</sub> / 3PGL<sub>2</sub>(9) (rk 4); U(4,3) polar graph; GQ(9,3) Sage cannot build a (280 117 44 52 ) that exists. Comment from Brouwer's database: pg(9,12,4)? Sage cannot build a (280 162 96 90 ) that exists. Comment from Brouwer's database: Sym(9) (rk 5)  Mathon & Rosa Sage cannot build a (280 243 210 216 ) that exists. Comment from Brouwer's database: Sage cannot build a (290 136 63 64 ) that exists. Comment from Brouwer's database: switch OA(17,9)+*; 2graph Sage cannot build a (290 153 80 81 ) that exists. Comment from Brouwer's database: S(2,9,145)?; 2graph Sage cannot build a (297 40 7 5 ) that exists. Comment from Brouwer's database: dual polar graph of lines in U<sub>5</sub>(2); GQ(8,4) Sage cannot build a (297 256 220 224 ) that exists. Comment from Brouwer's database: Sage cannot build a (300 65 10 15 ) that exists. Comment from Brouwer's database: NO<sup>,orth</sup>(5,5) Sage cannot build a (300 104 28 40 ) that exists. Comment from Brouwer's database: NO<sup></sup>(5,5) Sage cannot build a (300 195 130 120 ) that exists. Comment from Brouwer's database: Sage cannot build a (300 234 183 180 ) that exists. Comment from Brouwer's database: Sage cannot build a (323 160 78 80 ) that exists. Comment from Brouwer's database: pg(16,9,8)?; 2graph* Sage cannot build a (323 162 81 81 ) that exists. Comment from Brouwer's database: S(2,9,153)?; 2graph* Sage cannot build a (324 152 70 72 ) that exists. Comment from Brouwer's database: RSHCD<sup></sup>; 2graph Sage cannot build a (324 153 72 72 ) that exists. Comment from Brouwer's database: OA(18,9)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (324 170 88 90 ) that exists. Comment from Brouwer's database: OA(18,10)?; 2graph Sage cannot build a (324 171 90 90 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (325 60 15 10 ) that exists. Comment from Brouwer's database: NO<sup>+,orth</sup>(5,5); pg(12,4,2)? Sage cannot build a (325 144 68 60 ) that exists. Comment from Brouwer's database: NO<sup>+</sup>(5,5) Sage cannot build a (325 180 95 105 ) that exists. Comment from Brouwer's database: pg(12,14,7)? Sage cannot build a (325 264 213 220 ) that exists. Comment from Brouwer's database: Sage cannot build a (343 54 5 9 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Godsil92">Godsil</a>(q=7,r=4); GQ(6,8) Sage cannot build a (343 150 53 75 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Godsil92">Godsil</a>(q=7,r=2); pg(6,24,3)?; 2graph* Sage cannot build a (343 192 116 96 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (343 288 242 240 ) that exists. Comment from Brouwer's database: Sage cannot build a (344 168 92 72 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (344 175 78 100 ) that exists. Comment from Brouwer's database: pg(7,24,4)?; Taylor 2graph for U<sub>3</sub>(7) Sage cannot build a (351 126 45 45 ) that exists. Comment from Brouwer's database: Sage cannot build a (351 224 142 144 ) that exists. Comment from Brouwer's database: NO<sup></sup>(7,3) Sage cannot build a (362 171 80 81 ) that exists. Comment from Brouwer's database: switch OA(19,10)+*; switch skewhad<sup>2</sup>+*; 2graph Sage cannot build a (362 190 99 100 ) that exists. Comment from Brouwer's database: S(2,10,181)?; 2graph Sage cannot build a (378 52 1 8 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#CossidentePenttila05">CossidentePenttila hemisystem</a> in PG(3,5<sup>2</sup>) Sage cannot build a (378 116 34 36 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Muzychuk07">Muzychuk S6</a> (n=3,d=3) Sage cannot build a (378 117 36 36 ) that exists. Comment from Brouwer's database: pg(13,8,4)? Sage cannot build a (378 260 178 180 ) that exists. Comment from Brouwer's database: NO<sup>+</sup>(7,3) Sage cannot build a (378 261 180 180 ) that exists. Comment from Brouwer's database: Sage cannot build a (378 325 280 275 ) that exists. Comment from Brouwer's database: Sage cannot build a (399 198 97 99 ) that exists. Comment from Brouwer's database: pg(18,10,9)?; 2graph* Sage cannot build a (399 200 100 100 ) that exists. Comment from Brouwer's database: S(2,10,190)?; 2graph* Sage cannot build a (400 189 88 90 ) that exists. Comment from Brouwer's database: RSHCD<sup></sup>; 2graph Sage cannot build a (400 190 90 90 ) that exists. Comment from Brouwer's database: OA(20,10)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (400 209 108 110 ) that exists. Comment from Brouwer's database: OA(20,11)?; GoethalsSeidel(2,19); 2graph Sage cannot build a (400 210 110 110 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (416 100 36 20 ) that exists. Comment from Brouwer's database: G<sub>2</sub>(4).2 / J<sub>2</sub>.2; subconstituent of Suz graph Sage cannot build a (416 315 234 252 ) that exists. Comment from Brouwer's database: pg(15,20,12)? Sage cannot build a (441 56 7 7 ) that exists. Comment from Brouwer's database: GQ(8,6) Sage cannot build a (441 220 109 110 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Mathon78">Mathon</a>; OA(21,11)?; 2graph* Sage cannot build a (441 384 334 336 ) that exists. Comment from Brouwer's database: Sage cannot build a (496 240 120 112 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (496 255 126 136 ) that exists. Comment from Brouwer's database: NO<sup>+</sup>(10,2); GoethalsSeidel(3,15); pg(15,16,8)?; 2graph Sage cannot build a (512 70 6 10 ) that exists. Comment from Brouwer's database: GQ(7,9); from a hyperoval: projective 8ary [10,3] code with weights 8, 10 Sage cannot build a (512 73 12 10 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#FiedlerKlin98">FiedlerKlin</a>; <a href="srgtabrefs.html#Kohnert07">Kohnert</a>: projective binary [73,9] code with weights 32, 40 Sage cannot build a (512 133 24 38 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Godsil92">Godsil</a>(q=8,r=3); pg(7,18,2)? Sage cannot build a (512 196 60 84 ) that exists. Comment from Brouwer's database: pg(7,27,3); projective 8ary [28,3] code with weights 24, 28 Sage cannot build a (512 219 106 84 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#FiedlerKlin98">FiedlerKlin</a>; projective binary [219,9] code with weights 96, 112 Sage cannot build a (512 292 156 180 ) that exists. Comment from Brouwer's database: Sage cannot build a (512 315 202 180 ) that exists. Comment from Brouwer's database: Sage cannot build a (512 378 282 270 ) that exists. Comment from Brouwer's database: Sage cannot build a (512 438 374 378 ) that exists. Comment from Brouwer's database: Sage cannot build a (512 441 380 378 ) that exists. Comment from Brouwer's database: Sage cannot build a (528 255 126 120 ) that exists. Comment from Brouwer's database: NO<sup></sup>(10,2); <a href="srgtabrefs.html#Muzychuk07">Muzychuk S2</a> (r=4); 2graph Sage cannot build a (528 272 136 144 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (530 253 120 121 ) that exists. Comment from Brouwer's database: switch OA(23,12)+*; switch skewhad<sup>2</sup>+*; 2graph Sage cannot build a (530 276 143 144 ) that exists. Comment from Brouwer's database: S(2,12,265)?; 2graph Sage cannot build a (539 250 105 125 ) that exists. Comment from Brouwer's database: pg(10,24,5)?; 2graph* Sage cannot build a (539 288 162 144 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (540 224 88 96 ) that exists. Comment from Brouwer's database: NU(4,3); pg(14,15,6)? Sage cannot build a (540 264 138 120 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (540 275 130 150 ) that exists. Comment from Brouwer's database: GoethalsSeidel(5,11); pg(11,24,6)?; 2graph Sage cannot build a (540 315 186 180 ) that exists. Comment from Brouwer's database: Sage cannot build a (560 208 72 80 ) that exists. Comment from Brouwer's database: Sz(8) (rk 17); pg(13,15,5)? Sage cannot build a (560 351 222 216 ) that exists. Comment from Brouwer's database: Sage cannot build a (575 286 141 143 ) that exists. Comment from Brouwer's database: pg(22,12,11)?; 2graph* Sage cannot build a (575 288 144 144 ) that exists. Comment from Brouwer's database: S(2,12,276)?; 2graph* Sage cannot build a (576 275 130 132 ) that exists. Comment from Brouwer's database: RSHCD<sup></sup>; 2graph Sage cannot build a (576 276 132 132 ) that exists. Comment from Brouwer's database: OA(24,12)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (576 299 154 156 ) that exists. Comment from Brouwer's database: OA(24,13)?; GoethalsSeidel(2,23); 2graph Sage cannot build a (576 300 156 156 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (625 156 29 42 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Bouyukliev_et_al06">BouyuklievFackWillemsWinne</a>: projective 5ary [39,4] code with weights 30, 35 Sage cannot build a (625 208 63 72 ) that exists. Comment from Brouwer's database: vanLintSchrijver(1); CK  CY1: projective 5ary [52,4] code with weights 40, 45 Sage cannot build a (625 416 279 272 ) that exists. Comment from Brouwer's database: vanLintSchrijver(2) Sage cannot build a (625 468 353 342 ) that exists. Comment from Brouwer's database: Sage cannot build a (626 300 143 144 ) that exists. Comment from Brouwer's database: switch OA(25,13)+*; 2graph Sage cannot build a (626 325 168 169 ) that exists. Comment from Brouwer's database: S(2,13,313)?; 2graph Sage cannot build a (630 85 20 10 ) that exists. Comment from Brouwer's database: pg(17,4,2)  <a href="srgtabrefs.html#Haemers81">Haemers</a> Sage cannot build a (630 544 468 480 ) that exists. Comment from Brouwer's database: Sage cannot build a (640 71 6 8 ) that exists. Comment from Brouwer's database: Haemers(8); <a href="srgtabrefs.html#Muzychuk07">Muzychuk S6</a> (n=8,d=2) Sage cannot build a (640 72 8 8 ) that exists. Comment from Brouwer's database: GQ(9,7) Sage cannot build a (640 567 502 504 ) that exists. Comment from Brouwer's database: Sage cannot build a (640 568 504 504 ) that exists. Comment from Brouwer's database: Sage cannot build a (672 176 40 48 ) that exists. Comment from Brouwer's database: pg(11,15,3)? Sage cannot build a (672 495 366 360 ) that exists. Comment from Brouwer's database: NU(6,2) Sage cannot build a (675 336 166 168 ) that exists. Comment from Brouwer's database: pg(24,13,12)?; 2graph* Sage cannot build a (675 338 169 169 ) that exists. Comment from Brouwer's database: S(2,13,325)?; 2graph* Sage cannot build a (676 325 156 156 ) that exists. Comment from Brouwer's database: OA(26,13)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (676 350 180 182 ) that exists. Comment from Brouwer's database: OA(26,14)?; 2graph Sage cannot build a (693 180 51 45 ) that exists. Comment from Brouwer's database: U<sub>6</sub>(2) / 2<sup>9</sup>.U<sub>4</sub>(2); subconstituent of Fi<sub>22</sub> graph; U(6,2) polar graph; pg(20,8,5)? Sage cannot build a (693 512 376 384 ) that exists. Comment from Brouwer's database: Sage cannot build a (729 88 7 11 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Godsil92">Godsil</a>(q=9,r=5); GQ(8,10) Sage cannot build a (729 112 1 20 ) that exists. Comment from Brouwer's database: 3<sup>6</sup>.2.L3(4) (rk 3)  <a href="srgtabrefs.html#Hill73">Hill</a> cap: projective ternary [56,6] code with weights 36, 45; <a href="srgtabrefs.html#BondarenkoRadchenko12">BondarenkoRadchenko</a> Sage cannot build a (729 168 27 42 ) that exists. Comment from Brouwer's database: pg(8,20,2)  <a href="srgtabrefs.html#DeClerck_et_al02">Mathon</a>; <a href="srgtabrefs.html#Gulliver96">Gulliver</a>: projective ternary [84,6] code with weights 54, 63 Sage cannot build a (729 252 81 90 ) that exists. Comment from Brouwer's database: VNO<sup></sup>(6,3) affine polar graph; projective ternary [126,6] code with weights 81, 90 Sage cannot build a (729 280 103 110 ) that exists. Comment from Brouwer's database: 35set of type (2,5) in PG(2,9)  <a href="srgtabrefs.html#deResmini87">De Resmini</a>: projective 9ary [35,3] code with weights 30, 33 Sage cannot build a (729 308 127 132 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Gulliver96a">Gulliver</a>: projective ternary [154,6] code with weights 99, 108 Sage cannot build a (729 328 127 164 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Godsil92">Godsil</a>(q=9,r=2); pg(8,40,4)?; 2graph* Sage cannot build a (729 336 153 156 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#PenttilaRoyle95">Penttila & Royle</a>: projective 9ary [42,3] code with weights 36, 39 Sage cannot build a (729 392 211 210 ) that exists. Comment from Brouwer's database: Sage cannot build a (729 400 235 200 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (729 420 243 240 ) that exists. Comment from Brouwer's database: Sage cannot build a (729 448 277 272 ) that exists. Comment from Brouwer's database: Sage cannot build a (729 476 313 306 ) that exists. Comment from Brouwer's database: Sage cannot build a (729 560 433 420 ) that exists. Comment from Brouwer's database: Sage cannot build a (729 616 523 506 ) that exists. Comment from Brouwer's database: Sage cannot build a (729 640 562 560 ) that exists. Comment from Brouwer's database: Sage cannot build a (730 351 168 169 ) that exists. Comment from Brouwer's database: switch OA(27,14)+*; switch skewhad<sup>2</sup>+*; 2graph Sage cannot build a (730 360 195 160 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (730 369 168 205 ) that exists. Comment from Brouwer's database: pg(9,40,5)?; Taylor 2graph for U<sub>3</sub>(9) Sage cannot build a (730 378 195 196 ) that exists. Comment from Brouwer's database: S(2,14,365)?; 2graph Sage cannot build a (765 192 48 48 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#IoninKharaghani03">IoninKharaghani</a>; pg(16,11,4)? Sage cannot build a (765 572 427 429 ) that exists. Comment from Brouwer's database: Sage cannot build a (779 378 177 189 ) that exists. Comment from Brouwer's database: pg(18,20,9)?; 2graph* Sage cannot build a (779 400 210 200 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (780 380 190 180 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (780 399 198 210 ) that exists. Comment from Brouwer's database: GoethalsSeidel(3,19); pg(19,20,10)?; 2graph Sage cannot build a (783 390 193 195 ) that exists. Comment from Brouwer's database: pg(26,14,13)?; 2graph* Sage cannot build a (783 392 196 196 ) that exists. Comment from Brouwer's database: S(2,14,378)?; 2graph* Sage cannot build a (784 243 82 72 ) that exists. Comment from Brouwer's database: Mathon; OA(28,9)? Sage cannot build a (784 270 98 90 ) that exists. Comment from Brouwer's database: Mathon; OA(28,10)? Sage cannot build a (784 297 116 110 ) that exists. Comment from Brouwer's database: Mathon; OA(28,11)? Sage cannot build a (784 377 180 182 ) that exists. Comment from Brouwer's database: RSHCD<sup></sup>; 2graph Sage cannot build a (784 378 182 182 ) that exists. Comment from Brouwer's database: OA(28,14)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (784 405 208 210 ) that exists. Comment from Brouwer's database: OA(28,15)?; GoethalsSeidel(2,27); 2graph Sage cannot build a (784 406 210 210 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (784 486 298 306 ) that exists. Comment from Brouwer's database: OA(28,18)? Sage cannot build a (784 513 332 342 ) that exists. Comment from Brouwer's database: OA(28,19)? Sage cannot build a (784 540 368 380 ) that exists. Comment from Brouwer's database: OA(28,20)? Sage cannot build a (842 406 195 196 ) that exists. Comment from Brouwer's database: switch OA(29,15)+*; 2graph Sage cannot build a (842 435 224 225 ) that exists. Comment from Brouwer's database: S(2,15,421)?; 2graph Sage cannot build a (891 90 9 9 ) that exists. Comment from Brouwer's database: GQ(10,8) Sage cannot build a (891 800 718 720 ) that exists. Comment from Brouwer's database: Sage cannot build a (899 448 222 224 ) that exists. Comment from Brouwer's database: pg(28,15,14)?; 2graph* Sage cannot build a (899 450 225 225 ) that exists. Comment from Brouwer's database: S(2,15,435)?; 2graph* Sage cannot build a (900 435 210 210 ) that exists. Comment from Brouwer's database: OA(30,15)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (900 464 238 240 ) that exists. Comment from Brouwer's database: OA(30,16)?; 2graph Sage cannot build a (936 375 150 150 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#JankoKharaghani02">JankoKharaghani</a>; pg(25,14,10)? Sage cannot build a (936 560 334 336 ) that exists. Comment from Brouwer's database: Sage cannot build a (957 256 80 64 ) that exists. Comment from Brouwer's database: S(2,8,232) Sage cannot build a (957 700 507 525 ) that exists. Comment from Brouwer's database: pg(28,24,21) Sage cannot build a (962 465 224 225 ) that exists. Comment from Brouwer's database: switch OA(31,16)+*; switch skewhad<sup>2</sup>+*; 2graph Sage cannot build a (962 496 255 256 ) that exists. Comment from Brouwer's database: S(2,16,481)?; 2graph Sage cannot build a (975 462 205 231 ) that exists. Comment from Brouwer's database: pg(14,32,7)?; 2graph* Sage cannot build a (975 512 280 256 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (976 480 248 224 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (976 495 238 264 ) that exists. Comment from Brouwer's database: GoethalsSeidel(5,15); pg(15,32,8)?; 2graph Sage cannot build a (1024 231 38 56 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Polhill09">Polhill</a>; possibly projective 4ary [77,5] code with weights 56, 64 Sage cannot build a (1024 264 56 72 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Polhill09">Polhill</a>; pg(11,23,3)?; possibly projective 4ary [88,5] code with weights 64, 72 Sage cannot build a (1024 297 76 90 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Polhill09">Polhill</a>; possibly projective 4ary [99,5] code with weights 72, 80 Sage cannot build a (1024 330 98 110 ) that exists. Comment from Brouwer's database: <a href="srgtabrefs.html#Polhill08">Polhill</a>; pg(15,21,5)?; possibly projective 4ary [110,5] code with weights 80, 88 Sage cannot build a (1024 693 472 462 ) that exists. Comment from Brouwer's database: Sage cannot build a (1024 726 518 506 ) that exists. Comment from Brouwer's database: Sage cannot build a (1024 759 566 552 ) that exists. Comment from Brouwer's database: Sage cannot build a (1024 792 616 600 ) that exists. Comment from Brouwer's database: Sage cannot build a (1080 351 126 108 ) that exists. Comment from Brouwer's database: NO<sup>+</sup>(4,3) Sage cannot build a (1080 728 484 504 ) that exists. Comment from Brouwer's database: pg(26,27,18)  Mathon Sage cannot build a (1105 80 15 5 ) that exists. Comment from Brouwer's database: U(4,4) polar graph; GQ(16,4) Sage cannot build a (1105 1024 948 960 ) that exists. Comment from Brouwer's database: Sage cannot build a (1107 378 117 135 ) that exists. Comment from Brouwer's database: NO<sup></sup>(8,3) Sage cannot build a (1107 728 484 468 ) that exists. Comment from Brouwer's database: Sage cannot build a (1176 300 54 84 ) that exists. Comment from Brouwer's database: NO<sup></sup>(5,7) Sage cannot build a (1176 875 658 630 ) that exists. Comment from Brouwer's database: Sage cannot build a (1215 574 253 287 ) that exists. Comment from Brouwer's database: pg(14,40,7)?; 2graph* Sage cannot build a (1215 640 352 320 ) that exists. Comment from Brouwer's database: 2graph* Sage cannot build a (1216 600 312 280 ) that exists. Comment from Brouwer's database: 2graph Sage cannot build a (1216 615 294 328 ) that exists. Comment from Brouwer's database: GoethalsSeidel(6,15); pg(15,40,8)?; 2graph Sage cannot build a (1225 384 138 112 ) that exists. Comment from Brouwer's database: NO<sup>+</sup>(5,7) Sage cannot build a (1225 578 273 272 ) that exists. Comment from Brouwer's database: OA(35,17)?; Pasechnik(35) Sage cannot build a (1225 612 305 306 ) that exists. Comment from Brouwer's database: skewhad$^2$; OA(35,18)?; 2graph* Sage cannot build a (1225 646 339 342 ) that exists. Comment from Brouwer's database: OA(35,19)? Sage cannot build a (1225 840 567 595 ) that exists. Comment from Brouwer's database: pg(24,34,17)? Sage cannot build a (1226 595 288 289 ) that exists. Comment from Brouwer's database: switch skewhad<sup>2</sup>+*; 2graph Sage cannot build a (1226 630 323 324 ) that exists. Comment from Brouwer's database: S(2,18,613)?; 2graph Sage cannot build a (1288 495 206 180 ) that exists. Comment from Brouwer's database: Sage cannot build a (1288 792 476 504 ) that exists. Comment from Brouwer's database: M<sub>24</sub> / 2.M<sub>12</sub>; pairs of dodecads; pg(22,35,14)? Sage cannot build a (1295 646 321 323 ) that exists. Comment from Brouwer's database: pg(34,18,17)?; 2graph* Sage cannot build a (1295 648 324 324 ) that exists. Comment from Brouwer's database: S(2,18,630)?; 2graph* Sage cannot build a (1296 629 304 306 ) that exists. Comment from Brouwer's database: RSHCD<sup></sup>; 2graph Sage cannot build a (1296 630 306 306 ) that exists. Comment from Brouwer's database: OA(36,18)?; RSHCD<sup>+</sup>; 2graph Sage cannot build a (1296 665 340 342 ) that exists. Comment from Brouwer's database: OA(36,19)?; GoethalsSeidel(2,35); 2graph Sage cannot build a (1296 666 342 342 ) that exists. Comment from Brouwer's database: 2graph <BLANKLINE> In Andries Brouwer's database:  448 impossible entries  2950 undecided entries  1140 realizable entries (Sage misses 276 of them) ********************************************************************** 1 item had failures: 1 of 3 in sage.graphs.strongly_regular_db._check_database [94 tests, 1 failure, 43.92 s] sage t long src/sage/groups/perm_gps/permutation_groups_catalog.py
comment:34 Changed 4 years ago by
Why exactly are you seting this ticket to needs_work
? All tests pass on my machine.
comment:35 in reply to: ↑ 33 Changed 4 years ago by
comment:36 Changed 4 years ago by
 Status changed from needs_work to positive_review
comment:37 Changed 4 years ago by
 Status changed from positive_review to needs_work
Yes so if its not this ticket then its one of the dependencies. I'll leave it to you to figure out which of your tickets breaks the test.
comment:38 Changed 4 years ago by
This ticket has only one dependency, i.e. #18934. You must be confused.
comment:39 Changed 4 years ago by
comment:40 Changed 4 years ago by
I don't know what exactly you are doing, but unless there is something wrong with this branch as it is, please set it back to positive_review
.
comment:41 Changed 4 years ago by
By the way, all 'merge' operations that you may perform between those three tickets should result in a 'fastforward', as they are all linearly ordered.
comment:42 followup: ↓ 43 Changed 4 years ago by
There is something wrong with this branch, it doctests implementation details instead of mathematical truths. Hence it is so fragile that even you yourself can't avoid breaking it. You can take care of the problem here or in a subsequent ticket, I don't care which.
comment:43 in reply to: ↑ 42 Changed 4 years ago by
There is something wrong with this branch, it doctests implementation details instead of mathematical truths.
Wow. I could remove 50% of Sage's doctests with a rule like that.
Hence it is so fragile that even you yourself can't avoid breaking it. You can take care of the problem here or in a subsequent ticket, I don't care which.
Excellent. Then if you agree that rewriting the dependencies of 3 stacked tickets is a bad idea, then I chose to do it later.
The doctest counts the number of graphs that we are not able to build automatically. These doctests are very precious, and there are many like that in the combinat.design folder already. It is admittedly a mess during the early stages of the implementation, especially when you forget (as I did) to order everything linearly from the beginning.
When tickets will start getting merged it will become easier. Here my trouble today was with #18934, which is "not in a release beta" but "already closed". If not for that, I would have moved it atop of the others, and there would have been no work involved.
Nathann
comment:44 Changed 4 years ago by
Dima? Unless you can tell me what you request to be changed on this ticket, please set it back to its original status.
comment:45 followup: ↓ 47 Changed 4 years ago by
comment:46 followup: ↓ 48 Changed 4 years ago by
I have very similar failure if I test with long
. The relevant part of the git log is attached.
comment:47 in reply to: ↑ 45 Changed 4 years ago by
Of course you could alternatively run your own doctests before having #18988 reviewed, that would also avoid test failures.
Scuse me, can you show me this 'doctest failure' you mention? I do not see it. I load the branch, I run the tests, they pass. Something different happens on your computer?
Just set this ticket back to positive review once you have fixed #18988 or wherever you want to address it.
Tell me what you want to see fixed, and I will. If there is nothing to fix here, please change the status.
Nathann
comment:48 in reply to: ↑ 46 ; followup: ↓ 52 Changed 4 years ago by
I have very similar failure if I test with
long
. The relevant part of the git log is attached.
Then the answer is in your git log: there are commits from #18972 in your history, which have nothing to do there.
Nathann
comment:49 Changed 4 years ago by
comment:50 followup: ↓ 53 Changed 4 years ago by
They do. Have you found a proof of the contrary? You do not even have to merge them, they are linearly ordered already.
comment:51 Changed 4 years ago by
Unless you want also me to magically make them pass doctests with a nonreviewed ticket #18972, as Dima seems to expect?
comment:52 in reply to: ↑ 48 ; followup: ↓ 54 Changed 4 years ago by
Replying to ncohen:
I have very similar failure if I test with
long
. The relevant part of the git log is attached.Then the answer is in your git log: there are commits from #18972 in your history, which have nothing to do there.
These commits should not affect the outcome, or at least I don't see how they can. Or, if you like, I have weird test failures on my branch due to something in your already reviewed tickets...
comment:53 in reply to: ↑ 50 ; followup: ↓ 55 Changed 4 years ago by
comment:54 in reply to: ↑ 52 ; followup: ↓ 57 Changed 4 years ago by
These commits should not affect the outcome, or at least I don't see how they can.
Easy: you add constructions of strongly regular graphs. The only thing this doctest does is check the *COUNT* of them (note that the individual lines naming each graph are not check, except the first, because of '...'). Given that you add constructions, the final number changes, and the doctest breaks.
Or, if you like, I have weird test failures on my branch due to something in your already reviewed tickets...
Just load *ONLY* the branch, and you will not have any problem. If you add other commits, now, I can do no magic.
Nathann
comment:55 in reply to: ↑ 53 Changed 4 years ago by
Yes, comment:33
If you read his 'history' file you will see that he tested more commits than that. He also had some commits of hiw own patch (#18972) in his history. If you load only the branch on my tickets things work, but you can't expect me to fix in my branches the errors introduced on nonreviewed tickets. The only thing that it proves is that #18972 needs to be rebased on #18988. And that's clearly not my job.
Nathann
comment:56 followup: ↓ 59 Changed 4 years ago by
comment:33 is from the buildbot and does not include any nonreviewed tickets:
comment:57 in reply to: ↑ 54 ; followup: ↓ 58 Changed 4 years ago by
Replying to ncohen:
These commits should not affect the outcome, or at least I don't see how they can.
Easy: you add constructions of strongly regular graphs. The only thing this doctest does is check the *COUNT* of them (note that the individual lines naming each graph are not check, except the first, because of '...'). Given that you add constructions, the final number changes, and the doctest breaks.
Oh hell... How about we add a special tag (say, countexamples) to these counting test(s), so that they don't normally run.
Or, if you like, I have weird test failures on my branch due to something in your already reviewed tickets...
Just load *ONLY* the branch, and you will not have any problem. If you add other commits, now, I can do no magic.
The problem is that nobody expects the Spanish Inquisition hitting on your tests this way. Doctesting such counts is akin to doctesting number of Sage tests that pass...
comment:58 in reply to: ↑ 57 ; followup: ↓ 63 Changed 4 years ago by
The problem is that nobody expects the Spanish Inquisition hitting on your tests this way. Doctesting such counts is akin to doctesting number of Sage tests that pass...
Regardless of that, the doctests pass, in this ticket and in those above.
Nathann
comment:59 in reply to: ↑ 56 Changed 4 years ago by
comment:33 is from the buildbot and does not include any nonreviewed tickets:
Is this buildbot running beta0 (which does *not* include #18934) or is it running your own moreupdated relase (which includes #18934)?
comment:60 followup: ↓ 61 Changed 4 years ago by
The buildbot always merges dependencies first; Currently I'm at
d3a0be9 Trac #18989: Incorrect input_alphabet in FiniteStateMachine.disjoint_union 00f8736 Trac #18938: Refactor shortest paths 387fe06 Trac #17462: Remove the (deprecated) _boundary parameter d868995 Trac #18608: Arc method in BalancedIncompleteBlockDesign class 649bf59 Trac #18585: Comparison of sparse polynomials d9bb5de Trac #18978: gf2x fails to build with GCC 5.2 3c97405 Trac #18775: polytopes.icosidodecahedron and graphs.TruncatedIcosidodecahedralGraph af59a3f Trac #18977: ncurses fails to build with GCC 5.2 4f379dc Trac #18860: Faster Poyhedron.graph() 47f6780 Trac #18975: make searches caseinsensitive by default 50f503f Trac #18976: Update to IPython 3.2.1 8063cb3 Trac #18961: upgrade ECL to 15.3.7 d6a3379 Trac #18934: New (v,6,1)BIBD with v<=201 82513eb Trac #18089: Automaton.shannon_parry_markov_chain: New method 01a74d6 Trac #10194: Set factories 3b7932c Trac #18963: Remove 5 occurrences of FSMOldProcessOutput (Followup to #16133) 9559da6 Trac #18967: Silence the messages about deleting empty directories 0247d96 Trac #18742: interactive_simplex_method: Support several styles corresponding to major textbooks 571ad54 Trac #18910: Boost minimum spanning tree c33a40b Trac #18876: Boost CuthillMcKee, King Ordering 02125c0 Trac #18557: Implement FiniteStateMachine.disjoint_union (and .__or__) f4a0ac6 Trac #18556: FiniteStateMachine.is_deterministic: machines with >1 initial states are nondeterministic c0d4e06 Trac #18282: Fixes, cleanup and improvements to the default evaluation method for univariate polynomials b74bb0b Trac #12607: ChainComplex reports zero homology groups (depending on ChomP) d401fff Trac #18831: Hyperelliptic point counting various methods disagree edb1b08 Updated Sage version to 6.9.beta0
comment:61 in reply to: ↑ 60 Changed 4 years ago by
The buildbot always merges dependencies first; Currently I'm at
So that is your explanation. Yesterday, or that night, you ran the doctests on a version of Sage which included #18934. This branch, at that time, did not have #18934 as a dependency. This morning, I rebased this ticket (and those above) over #18934, and I fixed it. So now it should work, because of this rebasing. So unless you find something wrong with this branch, please set it back to its original status.
Nathann
comment:62 followup: ↓ 64 Changed 4 years ago by
And this is why it shouldn't be possible to change positively reviewed branches... we can implement a cooloff period just for you if you prefer ;)
comment:63 in reply to: ↑ 58 ; followup: ↓ 65 Changed 4 years ago by
As the reviewer, I hereby humbly beg for the _check_database()
test to be amended; either
suppress checking the actual numbers by ...
, or give it an extra optional tag so that it does not stand in the way.
comment:64 in reply to: ↑ 62 Changed 4 years ago by
And this is why it shouldn't be possible to change positively reviewed branches... we can implement a cooloff period just for you if you prefer ;)
Create a poll on sagedevel.
comment:65 in reply to: ↑ 63 ; followup: ↓ 66 Changed 4 years ago by
As the reviewer, I hereby humbly beg for the
_check_database()
test to be amended; either suppress checking the actual numbers by...
, or give it an extra optional tag so that it does not stand in the way.
If we do it now, I will have to remerge 3 linearly ordered patches again. So let's do that later.
Nathann
comment:66 in reply to: ↑ 65 Changed 4 years ago by
Replying to ncohen:
As the reviewer, I hereby humbly beg for the
_check_database()
test to be amended; either suppress checking the actual numbers by...
, or give it an extra optional tag so that it does not stand in the way.If we do it now, I will have to remerge 3 linearly ordered patches again. So let's do that later.
Can you do this on #18988, or whatever ticket that has the latest commits in this chain?
comment:67 Changed 4 years ago by
Yeah yeah. I'm against it, but after having been complaining pointlessly for 30 minutes on a ticket because you were all testing something different from the branch stored on this ticket, I won't even bother trying to explain.
Nathann
comment:68 Changed 4 years ago by
Easier to blame the doctest, of course.
comment:69 followup: ↓ 73 Changed 4 years ago by
Let's create another ticket for that. It's unrelated to the topic of #18988..
comment:70 Changed 4 years ago by
So? Are you now convinced that there is no broken doctest in this ticket, and that it can be set back to its original status ?
comment:71 followup: ↓ 72 Changed 4 years ago by
 Status changed from needs_work to positive_review
I'm not necessarily convinced but I can try again... hopefully I'll get through a testing cycle before the branch changes again ;)
comment:72 in reply to: ↑ 71 Changed 4 years ago by
I'm not necessarily convinced but I can try again... hopefully I'll get through a testing cycle before the branch changes again ;)
Yeah, sorry for that. I should have remembered to keep such tickets in a linear order at all times.
comment:73 in reply to: ↑ 69 Changed 4 years ago by
comment:74 Changed 4 years ago by
 Branch changed from u/ncohen/18948 to d1d25a03964f92c590449bebd359b21e7feaf349
 Resolution set to fixed
 Status changed from positive_review to closed
New commits:
trac XXX: Strongly Regular Graphs database