c_cpp/lib/klib/keigen.h

   1 #ifndef KEIGEN_H
   2 #define KEIGEN_H
   3
   4 #define KE_EXCESS_ITER (-1)
   5
   6 #ifdef __cplusplus
   7 extern "C" {
   8 #endif
   9
  10 /**
  11  * Compute eigenvalues/vectors for a dense symmetric matrix
  12  *
  13  * @param n       dimension
  14  * @param a       input matrix and eigenvalues on return ([n*n]; in & out)
  15  * @param v       eigenvalues ([n]; out)
  16  * @param cal_ev  compute eigenvectos or not (faster without vectors)
  17  * @param eps     precision (<=0 for default)
  18  * @param max_itr max iteration (<=0 for detaul)
  19  *
  20  * @return 0 on success; KE_EXCESS_ITER if too many iterations
  21  */
  22 int ke_eigen_sd(int n, double *a, double *v, int cal_ev, double eps, int max_iter);
  23
  24 /**
  25  * Transform a real symmetric matrix to a tridiagonal matrix
  26  *
  27  * @param n       dimension
  28  * @param q       input matrix and transformation matrix ([n*n]; in & out)
  29  * @param b       diagonal ([n]; out)
  30  * @param c       subdiagonal ([n]; out)
  31  */
  32 void ke_core_strq(int n, double *q, double *b, double *c);
  33
  34 /**
  35  * Compute eigenvalues and eigenvectors for a tridiagonal matrix
  36  *
  37  * @param n       dimension
  38  * @param b       diagonal and eigenvalues on return ([n]; in & out)
  39  * @param c       subdiagonal ([n]; in)
  40  * @param q       transformation matrix and eigenvectors on return ([n*n]; in & out)
  41  * @param cal_ev  compute eigenvectors or not (faster without vectors)
  42  * @param eps     precision
  43  * @param l       max iterations
  44  *
  45  * @return 0 on success; KE_EXCESS_ITER if too many iterations
  46  */
  47 int ke_core_sstq(int n, double *b, double *c, double *q, int cal_ev, double eps, int l);
  48
  49 #ifdef __cplusplus
  50 }
  51 #endif
  52
  53 #endif