[Nauty-list] Custom pruning in genbg

[Stephen Hartke]

I am resending this since the previous message was not approved to have
attachments more than 40K.  I have attached a patch giving the custom
pruning function I added to genbg.c---hopefully this will get through to the
list.

Thanks for any help or insights!
Stephen

---------- Forwarded message ----------
From: Stephen Hartke <hartke at gmail.com>
Date: 2011/7/20
Subject: Custom pruning in genbg
To: nauty-list at cs.anu.edu.au


genbg is a fantastic tool for investigating properties of hypergraphs!
Thanks for creating it!

I have a question about the custom pruning in genbg.c:

I created a custom pruning function in genbg.c (modified code is attached)
to print out information.  Unfortunately, it seems that the deg array does
not contain the degrees of the vertices of the graph passed in in g; see
attached output.  I tried the pruning function both as PRUNE1 and PRUNE2,
and the difficulty arises in both cases.  Am I accessing this information
incorrectly, or is there a bug?

Also, it was not clear to me how to calculate m for the passed in graph.
The function writeg6x seems to suggest that m is always 1.  Is this the
case?

Thanks for any help or insights!
Stephen
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./genbg 1 2 > output.txt
>A ./genbg n=1+2 e=0:2 d=0:0 D=2:1
>Z 3 graphs generated in 0.00 sec
prune: n1=1, n2=1, maxn2=2, m=1
  deg[0]=0, count=0, popcount=0
  deg[1]=0, count=0, popcount=0
prune: n1=1, n2=2, maxn2=2, m=1
  deg[0]=0, count=0, popcount=0
  deg[1]=0, count=0, popcount=0
  deg[2]=3, count=0, popcount=0
B?
prune: n1=1, n2=2, maxn2=2, m=1
  deg[0]=0, count=1, popcount=1
  deg[1]=0, count=0, popcount=0
  deg[2]=3, count=1, popcount=1
BO
prune: n1=1, n2=1, maxn2=2, m=1
  deg[0]=1, count=1, popcount=1
  deg[1]=1, count=1, popcount=1
prune: n1=1, n2=2, maxn2=2, m=1
  deg[0]=1, count=2, popcount=2
  deg[1]=1, count=1, popcount=1
  deg[2]=3, count=1, popcount=1
Bo
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