[Nauty-list] What is possible cause of this error? Thank you very much!

Gordon Royle gordon at csse.uwa.edu.au
Mon Mar 26 13:22:34 EST 2007

On 26/03/2007, at 11:12 AM, Anjie [Eric] Guo wrote:

> I am trying to write a function that takes a graph g and write a  
> canonically labelled isomorph of g into the graph canong. This  
> procedure worked perfectly when I was trying it out in the main  
> function, but turned out to cause memory error when I tried to  
> enclose it in a independent function. When I was debugging it, I  
> found out that the graph g was actually changed after I called nauty 
> (g, lab, ptn, NULL, orbits, &options, &stats, workspace, 50 * MAXM,  
> m, n, canong), although g is supposed to be read-only according to  
> the nauty User's Guide (Version 2.2). Hence I am wondering what  
> could be causing this situation? Thank you!

Almost certainly the error will be to do with how you are *calling*  
this function - in particular is the variable that you pass in for  
"canong" properly allocated including the necessary space declared  
for it?

If g has been changed, it suggests that you have accidentally got "g"  
and "canong" overlapping in memory..


Associate Professor Gordon Royle
Department of Computer Science & Software Engineering
University of Western Australia

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