topic Re: Lapack: DSTEVR produces SIGSEGV when all eigenvectors are q in Intel® oneAPI Math Kernel Library

Lapack: DSTEVR produces SIGSEGV when all eigenvectors are queried

clemens_adolphs — Wed, 18 Nov 2009 09:39:01 GMT

Dear all,

I am using DSTEVR to diagonalize a symmetric tridiagonal matrix. It works fine when I only want none or some of the eigenvectors. For a matrix of dimension N, computing the first N-1 eigenvectors/eigenvalues works fine.

However, if I want all eigenvectors, DSTEVR crashes with a segmentation fault in mkl_lapack_dlarre

A minimum example is

 #include  #include  using namespace std;  extern "C" {     void dstevr(   char *jobz, char *range, int *n, double * d, double *e, double *vl, double *vu, int *il,                      int *iu, double *abstol, int *m, double *w, double *z, int *ldz, int *isuppz, double *work,                      int *lwork, int *iwork, int *liwork, int *info);     void dstevr_(   char *jobz, char *range, int *n, double * d, double *e, double *vl, double *vu, int *il,                      int *iu, double *abstol, int *m, double *w, double *z, int *ldz, int *isuppz, double *work,                      int *lwork, int *iwork, int *liwork, int *info); }  int main() {     int n = 3;     double* d = (double*) malloc(n*sizeof(double));     double* e = (double*) malloc((n-1)*sizeof(double));      d[0] = 1;     d[1] = 2;     d[2] = 3;     e[0] = 0.2;     e[1] = 0.1;      double* ee = (double*) malloc(n*sizeof(double));     double* ev = (double*) malloc(n*n*sizeof(double));     //Fill with stuff so we see what dstevr has changed     for (int i = 0; i < n; i++)         for (int j = 0; j < n; j++)             ev[i*n+j] = (double)(i*n+j);      //Allocate work arrays     int lwork = 60*n;     int liwork = 30*n;     double* work = (double*) malloc(lwork*sizeof(double));     int* iwork = (int*) malloc(liwork*sizeof(int));      //Prepare arguments to FORTRAN function     char jobz = 'V';     char range = 'A';     double abstol = 0.0;     int m;     int ldz = n;     int* isuppz = (int*) malloc(sizeof(int)*2*n);     for (int i = 0; i < 2 * n; i++)         isuppz = 0;      int result = 0;     double vl = 0, vu = 0;     int il = 1, iu = n - 1;      dstevr_(&jobz, &range, &n, d, e, &vl, &vu, &il, &iu, &abstol, &m, ee, ev, &ldz, isuppz, work, &lwork, iwork, &liwork,&result); //    int dummy = -1; //    dstevr(&jobz, &range, &n, d, e, &vl, &vu, &il, &iu, &abstol, &m, ee, ev, &ldz, isuppz, work, &dummy, iwork, &dummy ,&result); //    cout << "Optimal lwork: " << (int) work[0] << "Optmial liwork" << iwork[0] << endl;      for (int i = 0; i < n; i++)     {         for (int j = 0; j < n; j++)             cout << ev[i*n+j] << "\t";         cout << endl;     }     cout << "ISUPPZ: ";     for (int i = 0; i < 2 * n; i++)         cout << isuppz << " ";     cout << endl;       return 0; }

I am linking against -lmkl, but it doesn't really matter.

The same code runs fine without segmentation faults if linked against other lapack implementations.

The MKL version in use is 10.0.1.014

Re: Lapack: DSTEVR produces SIGSEGV when all eigenvectors are q

Gennady_F_Intel — Wed, 18 Nov 2009 11:44:48 GMT

Quoting - clemens_adolphs

Dear all,
I am using DSTEVR to diagonalize a symmetric tridiagonal matrix. It works fine when I only want none or some of the eigenvectors. For a matrix of dimension N, computing the first N-1 eigenvectors/eigenvalues works fine.

However, if I want all eigenvectors, DSTEVR crashes with a segmentation fault in mkl_lapack_dlarre

A minimum example is
#include #include using namespace std; extern "C" { void dstevr( char *jobz, char *range, int *n, double * d, double *e, double *vl, double *vu, int *il, int *iu, double *abstol, int *m, double *w, double *z, int *ldz, int *isuppz, double *work, int *lwork, int *iwork, int *liwork, int *info); void dstevr_( char *jobz, char *range, int *n, double * d, double *e, double *vl, double *vu, int *il, int *iu, double *abstol, int *m, double *w, double *z, int *ldz, int *isuppz, double *work, int *lwork, int *iwork, int *liwork, int *info); } int main() { int n = 3; double* d = (double*) malloc(n*sizeof(double)); double* e = (double*) malloc((n-1)*sizeof(double)); d[0] = 1; d[1] = 2; d[2] = 3; e[0] = 0.2; e[1] = 0.1; double* ee = (double*) malloc(n*sizeof(double)); double* ev = (double*) malloc(n*n*sizeof(double)); //Fill with stuff so we see what dstevr has changed for (int i = 0; i < n; i++) for (int j = 0; j < n; j++) ev[i*n+j] = (double)(i*n+j); //Allocate work arrays int lwork = 60*n; int liwork = 30*n; double* work = (double*) malloc(lwork*sizeof(double)); int* iwork = (int*) malloc(liwork*sizeof(int)); //Prepare arguments to FORTRAN function char jobz = 'V'; char range = 'A'; double abstol = 0.0; int m; int ldz = n; int* isuppz = (int*) malloc(sizeof(int)*2*n); for (int i = 0; i < 2 * n; i++) isuppz = 0; int result = 0; double vl = 0, vu = 0; int il = 1, iu = n - 1; dstevr_(&jobz, &range, &n, d, e, &vl, &vu, &il, &iu, &abstol, &m, ee, ev, &ldz, isuppz, work, &lwork, iwork, &liwork,&result); // int dummy = -1; // dstevr(&jobz, &range, &n, d, e, &vl, &vu, &il, &iu, &abstol, &m, ee, ev, &ldz, isuppz, work, &dummy, iwork, &dummy ,&result); // cout << "Optimal lwork: " << (int) work[0] << "Optmial liwork" << iwork[0] << endl; for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) cout << ev[i*n+j] << "t"; cout << endl; } cout << "ISUPPZ: "; for (int i = 0; i < 2 * n; i++) cout << isuppz << " "; cout << endl; return 0; }

I am linking against -lmkl, but it doesn't really matter.

The same code runs fine without segmentation faults if linked against other lapack implementations.

The MKL version in use is 10.0.1.014

the same as http://software.intel.com/en-us/forums/showthread.php?t=69963