Re: [igraph] Comparing large graphs

[Charles Novaes de Santana]

And I did my debug using GNU gdb.

Charles

On Wed, Dec 5, 2012 at 10:04 PM, Charles Novaes de Santana
<address@hidden> wrote:
> Sorry. I am using Gcc 4.6.3 on a Ubuntu 12.04.
>
> Thanks,
>
> Charles
> On Wed, Dec 5, 2012 at 10:01 PM, Gábor Csárdi <address@hidden> wrote:
>> Charles,
>>
>> what is your platform? OS, OS version, C compiler version? Anything else
>> that you might think is needed to reproduce this?
>>
>> G.
>>
>>
>> On Wed, Dec 5, 2012 at 3:44 PM, Charles Novaes de Santana
>> <address@hidden> wrote:
>>>
>>> Just to explay why I think my problem with the "infinity" values:
>>>
>>> Because I tryied to debug my program and I got the following message:
>>>
>>> Program received signal SIGSEGV, Segmentation fault.
>>> igraph_vector_fill (v=0xbffff6ac, e=inf) at vector.pmt:682
>>> 682         *ptr = e;
>>>
>>> As the value received by function igraph_vector_fill is "e=inf" I
>>> suppose it was my problem.
>>>
>>> Best,
>>>
>>> Charles
>>>
>>> On Wed, Dec 5, 2012 at 9:40 PM, Charles Novaes de Santana
>>> <address@hidden> wrote:
>>> > Thank you again, Tamás. You were absolutely right about my mistake in
>>> > printing the matrix. I did a simple cast and my matrix operations
>>> > worked fine.
>>> >
>>> > But I still have problems with the "infinity" given by the
>>> > shortest_paths function. I did the function you suggested me (to
>>> > replace all IGRAPH_INFINITY by zeros), but I have problems in the
>>> > calculation of the shortest paths itself, before I have the
>>> > opportunity to replace the "inifinity" by "zero".
>>> >
>>> > If you don't mind, I am sending attached to this message a small
>>> > program with the part of my code where I got the error. And an example
>>> > of a network I am studying. Maybe it is an error in the format of my
>>> > network and I can not understand it yet. Or maybe it is because my
>>> > network is very sparse.
>>> >
>>> > Thank you very much for your attention,
>>> >
>>> > Best,
>>> >
>>> > Charles
>>> >
>>> > /*SOURCE CODE*/
>>> >
>>> > #include<igraph.h>
>>> >
>>> > int main(void){
>>> >         igraph_t g1;
>>> >         igraph_matrix_t l1;
>>> >         igraph_vs_t vertices;
>>> >
>>> >         int i,j;
>>> >         FILE *ifile1;
>>> >
>>> > /*Reading the network*/
>>> >         ifile1=fopen("./network.net", "r");
>>> >         if (ifile1==0) {return 10;}
>>> >         igraph_read_graph_pajek(&g1, ifile1);
>>> >         fclose(ifile1);
>>> >
>>> > /*Initializing the matrix l1 and the vector of vertices*/
>>> >
>>> >         igraph_vs_all(&vertices);
>>> >         igraph_matrix_init(&l1, 0, 0);
>>> >
>>> > /*Calculating the shortest paths*/
>>> >
>>> > igraph_shortest_paths(&g1,&l1,vertices,vertices,IGRAPH_ALL);
>>> >
>>> > /*Desconstructors*/
>>> >         igraph_matrix_destroy(&l1);
>>> >         igraph_vs_destroy(&vertices);
>>> >         igraph_destroy(&g1);
>>> >         return;
>>> > }
>>> >
>>> >
>>> >         igraph_matrix_destroy(&l1);
>>> >         igraph_vs_destroy(&vertices);
>>> >         igraph_destroy(&g1);
>>> >
>>> >
>>> > On Wed, Dec 5, 2012 at 10:32 AM, Tamás Nepusz <address@hidden> wrote:
>>> >>> First, I was wondering if Igraph considers IGRAPH_INFINITY as zero or
>>> >>> as other value.
>>> >> IGRAPH_INFINITY is infinity, period. It is there only to provide us
>>> >> with a sort-of-platform-independent way to refer to infinity.
>>> >>
>>> >>> I am working with shortest-paths matrices and I would
>>> >>> like the distance between two vertices that can not reach each other
>>> >>> to be zero.
>>> >> Well, you have to check all the cells in the matrix and if a cell is
>>> >> equal to IGRAPH_INFINITY, you have to set it to  zero.
>>> >>
>>> >>> (I tryied to do "igraph_matrix_scale(matrix,1./2)" and it gave
>>> >>> me a zero-matrix).
>>> >> Theoretically it should work; there is no limitation on
>>> >> igraph_matrix_scale to work on integer values only. I have just tested 
>>> >> it on
>>> >> my machine and it worked for me, so I guess that the error is somewhere
>>> >> else; for instance, in the way you print the values.
>>> >>
>>> >> Cheers,
>>> >> --
>>> >> T.
>>> >>
>>> >>
>>> >> _______________________________________________
>>> >> igraph-help mailing list
>>> >> address@hidden
>>> >> https://lists.nongnu.org/mailman/listinfo/igraph-help
>>> >
>>> >
>>> >
>>> > --
>>> > Um axé! :)
>>> >
>>> > --
>>> > Charles Novaes de Santana
>>> > http://www.imedea.uib-csic.es/~charles
>>> > PhD student - Global Change
>>> > Laboratorio Internacional de Cambio Global
>>> > Department of Global Change Research
>>> > Instituto Mediterráneo de Estudios Avanzados(CSIC/UIB)
>>> > Calle Miquel Marques 21, 07190
>>> > Esporles - Islas Baleares - España
>>> >
>>> > Office phone - +34 971 610 896
>>> > Cell phone - +34 660 207 940
>>>
>>>
>>>
>>> --
>>> Um axé! :)
>>>
>>> --
>>> Charles Novaes de Santana
>>> http://www.imedea.uib-csic.es/~charles
>>> PhD student - Global Change
>>> Laboratorio Internacional de Cambio Global
>>> Department of Global Change Research
>>> Instituto Mediterráneo de Estudios Avanzados(CSIC/UIB)
>>> Calle Miquel Marques 21, 07190
>>> Esporles - Islas Baleares - España
>>>
>>> Office phone - +34 971 610 896
>>> Cell phone - +34 660 207 940
>>>
>>> _______________________________________________
>>> igraph-help mailing list
>>> address@hidden
>>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>>
>>
>>
>>
>> --
>> Gabor Csardi <address@hidden>     MTA KFKI RMKI
>>
>>
>> _______________________________________________
>> igraph-help mailing list
>> address@hidden
>> https://lists.nongnu.org/mailman/listinfo/igraph-help
>>
>
>
>
> --
> Um axé! :)
>
> --
> Charles Novaes de Santana
> http://www.imedea.uib-csic.es/~charles
> PhD student - Global Change
> Laboratorio Internacional de Cambio Global
> Department of Global Change Research
> Instituto Mediterráneo de Estudios Avanzados(CSIC/UIB)
> Calle Miquel Marques 21, 07190
> Esporles - Islas Baleares - España
>
> Office phone - +34 971 610 896
> Cell phone - +34 660 207 940



-- 
Um axé! :)

--
Charles Novaes de Santana
http://www.imedea.uib-csic.es/~charles
PhD student - Global Change
Laboratorio Internacional de Cambio Global
Department of Global Change Research
Instituto Mediterráneo de Estudios Avanzados(CSIC/UIB)
Calle Miquel Marques 21, 07190
Esporles - Islas Baleares - España

Office phone - +34 971 610 896
Cell phone - +34 660 207 940