Re: [Help-gsl] segmentation fault while using gsl_linalg_complex_LU_decomposition

[Greg Lyukshin]

Segmentation Fault Error implies that you are trying to access
unallocated(non-assigned) memory. One thing however, It compiles just fine
in Visual Studio(it happens sometimes) with two warnings, which I don't
think causing the error in this case. So I can't really debug it. You should
debug it and let us know, which line causes the segfault error.



On Mon, Aug 8, 2011 at 3:04 PM, Владимир Дрынкин <address@hidden
> wrote:

> Hello, all!!
>
> Tonight i was trying to make a c++ class for working with gsl_complex
> matrices. But when i compiled my program, i got segmentation fault
> error :(
> The code was built on the mac os x lion and debian 6 stable, but the
> result was the same. Can you help me, what's wrong with my code?
>
> Thanks a lot, Vladimir.
>
> [CODE]
> #include <iostream>
> #include <gsl/gsl_matrix.h>
> #include <gsl/gsl_blas.h>
> #include <gsl/gsl_complex.h>
> #include <gsl/gsl_complex_math.h>
> #include <gsl/gsl_rng.h>
> #include <gsl/gsl_linalg.h>
> using namespace std;
>
> class matrix
> {
>    gsl_matrix_complex *mtrx;
> public:
>    size_t rows;
>    size_t cols;
>    matrix();
>    matrix(const size_t r, const size_t c);
>    ~matrix();
>    matrix(const matrix &rhs);
>    matrix operator=(const matrix &rhs);
>    matrix operator+(const matrix &rhs);
>    matrix operator-(const matrix &rhs);
>    matrix operator*(const matrix &rhs);
>    void print();
>    void randomize();
>    matrix inverse();
>    gsl_complex &at(size_t r, size_t c);
> };
>
> matrix::matrix()
> {
>    mtrx = gsl_matrix_complex_alloc(1, 1);
>    rows = cols = 1;
>    cout << "Created uninitialised default 1x1 matrix\n";
> }
>
> matrix::matrix(const size_t r, const size_t c)
> {
>    mtrx = gsl_matrix_complex_alloc(r, c);
>    rows = r;
>    cols = c;
>    cout << "Created uninitialised " << rows << "x" << cols << " matrix\n";
> }
>
> matrix::~matrix()
> {
>    gsl_matrix_complex_free(mtrx);
>    cout << "The matrix has been deallocated\n";
> }
>
> matrix::matrix(const matrix &rhs)
> {
>    mtrx = gsl_matrix_complex_alloc(rhs.rows, rhs.cols);
>    rows=rhs.rows;
>    cols=rhs.cols;
>    int a = gsl_matrix_complex_memcpy(mtrx, rhs.mtrx);
>    cout << a << " - the code, returned by copy constructor (0=Success)\n";
> }
>
> matrix matrix::operator=(const matrix &rhs)
> {
>    gsl_matrix_complex_memcpy(mtrx, rhs.mtrx);
>    return *this;
> }
>
> matrix matrix::operator+(const matrix &rhs)
> {
>    matrix temp(rows, cols);
>    temp = *this;
>    gsl_matrix_complex_add(temp.mtrx, rhs.mtrx);
>    return temp;
> }
>
> matrix matrix::operator-(const matrix &rhs)
> {
>    matrix temp(rows, cols);
>    temp = *this;
>    gsl_matrix_complex_sub(temp.mtrx, rhs.mtrx);
>    return temp;
> }
>
> matrix matrix::operator*(const matrix &rhs)
> {
>    matrix temp(rows, rhs.cols);
>    gsl_blas_zgemm(CblasNoTrans, CblasNoTrans, gsl_complex_rect(1.0,
> 0.0), mtrx, rhs.mtrx, gsl_complex_rect(0.0, 0.0), temp.mtrx);
>    return temp;
> }
>
> void matrix::print()
> {
>    gsl_matrix_complex_fprintf(stdout, mtrx, "%f");
> }
>
> void matrix::randomize()
> {
>    const gsl_rng_type *T;
>    gsl_rng *r;
>    T = gsl_rng_taus2;
>    r = gsl_rng_alloc(T);
>    for (size_t n=0; n<rows; n++)
>    {
>        for(size_t m=0; m<cols; m++)
>        {
>            this->at(n,m)=gsl_complex_rect((double)gsl_rng_get(r)*0.0000001,
> (double)gsl_rng_get(r)*0.0000001);
>        }
>    }
>    gsl_rng_free(r);
> }
>
> matrix matrix::inverse()
> {
>    int *signum;
>    gsl_permutation *p;
>    p = gsl_permutation_alloc(rows);
>    matrix temp = *this;
>    matrix temp_inv(rows, cols);
>    gsl_linalg_complex_LU_decomp(temp.mtrx, p, signum);
>    temp.print();
>    gsl_linalg_complex_LU_invert(temp.mtrx, p, temp_inv.mtrx);
>    return temp_inv;
> }
>
> gsl_complex &matrix::at(size_t r, size_t c)
> {
>    gsl_complex *p;
>    p = gsl_matrix_complex_ptr(mtrx, r, c);
>    if(p!=0) return *p;
> }
>
> int main (int argc, const char * argv[])
> {
>    matrix b(3,3);
>    b.randomize();
>    b.inverse();
>    return 0;
> }
> [/CODE]
>
> _______________________________________________
> Help-gsl mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/help-gsl
>



-- 
Greg Lyukshin