[Nauty] forbidden subgraphs in directed graphs

[Chad Brewbaker]

Opps. Directed graphs, no symetry.

Replace "j=i" with "j=0" in the for loops.
> Those graphs are easy to recognize, write a filter. Dissalow all L shapes in the

> adjacency matrix.
> 
> 
>   1  2  3  4
> 1    X
> 2
> 3    X     X
> 4
> 
> OR
> 
>   4  2  3  1
> 4    
> 2
> 3 X  X    
> 1    X
> 
> /*Skeleton program
> Usage:
> geng <args> | Lfilter >myFile
> */
> 
> 
> int i,j,k;
> int colCount[n];
> int rowCount[n]
> 
> for(i=0;i<10;i++){
> colCount[i]=rowCount[i]=0;
> }
> 
> /*Mark possible trouble makers*/
> for(i=0;i<n;i++){
> for(j=i;j<n;j++){
> if(graph[i][j]){
> colCount[j]++;
> rowCount[i]++;
> }
> }
> }
> /*Throw out graphs with "L" in them*/
> for(i=0;i<n;i++){
> for(j=i;j<n;j++){
> if(graph[i][j]){
> if(colCount[j]>1 && rowCount[i]>1)
> rejectGraph();
> }
> }
> }
> acceptGraph();
> 
> 
> /*end program*/
> 
> To read the graph from g6 format I have some code:
> http://www.public.iastate.edu/~crb002/code/readg6.c
> 
> 
> 
> 
> 
> 
> > 
> > I think, we talked about this some time ago, I don't remember  exactly.
> > Or maybe there is something new...
> >  
> > I can do this with undirected graphs using geng, but I need it with
> > directed graphs too.
> >  
> 
> 
> 
> 
> 
> 
> 
> 
> > 
> > I think, we talked about this some time ago, I don't remember  exactly.
> > Or maybe there is something new...
> >  
> > I can do this with undirected graphs using geng, but I need it with
> > directed graphs too.
> >  
> > e.g. I want all acyclic digraphs not containing the "N" digraph   
> > 1->2,3->2,3->4
> >  
> >  
> >  
> > Guenter.
> > 
> 
> 
> 
> 
> 
> 
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