Re: [igraph] Using std::vector with Igraph

[Gábor Csárdi]

Hmmm, there is a slight confusion here I think. If you want to store long integers in an igraph vector_t, use need to use the type igraph_vector_long_t. igraph_vector_ptr_t contains pointers to externally allocated objects.

Gabor

On Mon, Apr 23, 2012 at 5:50 AM, Ruben Vacing <address@hidden> wrote:

I've been trying to find a really function that let me convert from std::vector of vector to igraph_vector_ptr_t and the opposite way.
The reason is, there are different classes like a std::sort, std::unique and others, that let us manipulate vectors, this function do not exist in Igraph libraries, because the library is a C library.
The next code only show the code to convert from std::vector to igraph_vector_ptr_t, the problem is that it doesn't work, please help me to help me to improve it. This code it doesn't work :(

#include <igraph.h>

#include <fstream>
#include <iostream>

#include <stdlib.h>
#include <vector>

#include <algorithm>

using namespace std;


void print_vector(igraph_vector_t *v, FILE *f) {


  long int i;
  long int l=igraph_vector_size(v);


  for (i=0; i<l; i++) {


    fprintf(f, " %li", (long int) VECTOR(*v)[i]);


  }
  fprintf(f, "\n");

}

void Stl_To_Igraph_vector_ptr_t(std::vector< std::vector< long int > > & vectR, igraph_vector_ptr_t * vl) {


      long int i,j,n;


      igraph_vector_t vt;
      igraph_vector_init(&vt,4);

      for (i = 0; i< 2; i++) {


            for (j = 0; j< 4; j++) {


                //cout << vectR.at(i).at(j) << " ";
                VECTOR(vt)[j]=vectR.at(i).at(j);


            }
            //cout<<endl;
            igraph_vector_ptr_set(vl, i,&vt);


      }
}

int main() {


  // Set STL Vectors
  std::vector< std::vector< long int > > vectR;


  std::vector<long int> vectRi1,vectRi2;

  long int myarray1 [] = { 1,2,3,4 };


  long int myarray2 [] = { 5,6,7,8 };



  vectRi1.insert(vectRi1.begin(), myarray1,  myarray1+4);


  vectRi2.insert(vectRi2.begin(), myarray2,  myarray2+4);



  vectR.push_back(vectRi1);
  vectR.push_back(vectRi2);



  // Convert From Stl vector to Igraph_vector_ptr_t
  igraph_vector_ptr_t vIgraph;

  igraph_vector_ptr_init(&vIgraph, 2);


  Stl_To_Igraph_vector_ptr_t(vectR, &vIgraph);


  // Print and distroyed
  long int i;

  for (i=0; i<igraph_vector_ptr_size(&vIgraph); i++) {


    print_vector((igraph_vector_t *)VECTOR(vIgraph)[i],stdout);


    igraph_vector_destroy((igraph_vector_t *)VECTOR(vIgraph)[i]);

    free((igraph_vector_t *)VECTOR(vIgraph)[i]);

  }

  return 0;
}

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--
Gabor Csardi <address@hidden>     MTA KFKI RMKI