Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.soft-sys.math.mathematica > #3454

Re: Mathematica 8 bug (related to Graph[])

From Szabolcs <szhorvat@gmail.com>
Newsgroups comp.soft-sys.math.mathematica
Subject Re: Mathematica 8 bug (related to Graph[])
Date 2011-07-02 09:06 +0000
Organization Steven M. Christensen and Associates, Inc and MathTensor, Inc.
Message-ID <iumn29$ac1$1@smc.vnet.net> (permalink)

Show all headers | View raw


On Saturday, March 19, 2011 11:19:10 AM UTC+1, Szabolcs wrote:
> Dear MathGroup members,
> 
> There appears to be another bug in graph processing functions:
> 
> In[1]:= jj = Subgraph[Graph[{1, 2, 3, 4}, {3 -> 4}], {1, 2, 3}]
> 
> Out[1]= 
> 
> 
> In[2]:= IsomorphicGraphQ[jj, Graph[{1, 2, 3}, {}]]
> 
> Out[2]= False
> 
> In[3]:= InputForm[jj]
> 
> Out[3]//InputForm=
> Graph[{1, 2, 3}, {}]
> 
> Strangely, if I copy and paste the output from Out[1] into the
> IsomorphicGraphQ[] function, then the problem doesn't manifest
> itself!  To reproduce it, evaluate the input exactly as shown above
> (try in a new session).  Generally, any action that pulls the graph-
> expression through the front-end seems to "fix" the problem.
> 
> Can you reproduce the bug in Mathematica 8.0.1?
> 

A possible workaround to this is applying Uncompress@Compress to the corrupted graph before testing for isomorphism.  

Back to comp.soft-sys.math.mathematica | Previous | Next | Find similar | Unroll thread


Thread

Re: Mathematica 8 bug (related to Graph[]) Szabolcs <szhorvat@gmail.com> - 2011-07-02 09:06 +0000

csiph-web