Re: [Help-gsl] gsl_matrix *p Pointer in Object

[Thomas Schmitt]

Hi, 
the gsl_matrix_view makes sense because i want to parse from a vector
that i read from a csv-file. Every instance of the class gets an
different vector. I attach the complete code.....and again thanks very
much for your help!!!!

/*
 * GaussMatrix.h
 *
 *  Created on: 17.07.2009
 *      Author: freak
 */

#ifndef GAUSSMATRIX_H_
#define GAUSSMATRIX_H_
#include <gsl/gsl_matrix.h>
#include <vector>
namespace std {

class GaussMatrix:public gsl_matrix {
private:
        double * _array;
        void ProcessArray ( const double * , size_t numDoubles ) ;
        unsigned int _rows,_columns, k, l;


public:
        gsl_matrix * p_matrix;
        GaussMatrix(vector<double> init_vector, unsigned int rows, unsigned int
columns );
        void print_matrix();
        //virtual ~GaussMatrix();

};

}

#endif /* GAUSSMATRIX_H_ */

/*
 * GaussMatrix.cpp
 *
 *  Created on: 17.07.2009
 *      Author: freak
 */

#include "GaussMatrix.h"
#include <iostream>
#include <vector>
#include <string>

namespace std {

GaussMatrix::GaussMatrix(vector<double> init_vector, unsigned int rows,
unsigned int columns) {

        cout << init_vector[0] << endl;
        _rows = rows;_columns=columns;
        ProcessArray ( &init_vector[0], init_vector.size() );
        cout << init_vector[0] << endl;
        _array = &init_vector[0];
        gsl_matrix_view a = gsl_matrix_view_array( _array, _rows, _columns );
        GaussMatrix::p_matrix = gsl_matrix_calloc(rows,columns);
        GaussMatrix::p_matrix = &a.matrix;

        cout << "pointer value:" << p_matrix << endl;


               for (int i = 0; i < 2; i++)  /* OUT OF RANGE ERROR */
                 for (int j = 0; j < 2; j++)
                   printf ("n(%d,%d) = %g\n", i, j,
                           gsl_matrix_get (p_matrix, i, j));


}

//GaussMatrix::~GaussMatrix() {
        // TODO Auto-generated destructor stub
//}

void GaussMatrix::ProcessArray ( const double * , size_t numDoubles )
{};

void GaussMatrix::print_matrix(){
        for (int i = 0; i < 2; i++)  /* OUT OF RANGE ERROR */
                         for (int j = 0; j < 2; j++)
                           printf ("m(%d,%d) = %g\n", i, j,
                                   gsl_matrix_get ( p_matrix, i, j));

}



}

and the main:


#include <fstream>
#include <iostream>
#include <map>
#include <vector>
#include <gsl/gsl_matrix.h>
#include <gsl/gsl_linalg.h>
#include "CalcPara.h"
#include <gsl/gsl_blas.h>
#include "CsvAutomation/CsvtoArray.h"
#include "GaussMatrix.h"

using namespace std;



int main() {


        fstream infile("input.csv",ios::in);
        vector<double> p_values;
        CsvtoArray toarray;
        /*
         * This method just generates a vector from the read values
         */
        toarray.csv_getArray_byName( infile,"P =", 1 , p_values);


        GaussMatrix gaus(p_values, 2, 2);
        gaus.print_matrix();
return 0;

}



Am Dienstag, den 21.07.2009, 21:43 +0200 schrieb Frank Reininghaus:
> Hi,
> 
> On Tuesday 21 July 2009 21:12:25 Thomas Schmitt wrote:
> > you're right, the calloc doesn't make sense!! But the line
> > GaussMatrix::p_matrix = &a.matrix;
> > should give me a pointer to the view i create.....but if i try to call
> > the pointer later in a function of the class(it just prints out the
> > matrix) 
> > i get different values than the ones i initialized.
> 
> the calloc made more sense to me than this very strange thing you're doing 
> with the gsl_matrix_view and the vector<double> in the class constructor. If 
> you pass the same "init_vector" to the constructor of each class instance, 
> all 
> instances will share the same matrix data, so manipulations of one instance 
> will also affect the others.
> 
> But again, it's impossible to fully analyse your problem without the code.
> 
> Cheers
> Frank