tests/tbeyn.c

   1 #include <qpms/beyn.h>
   2 #include <stdio.h>
   3 #include <string.h>
   4
   5 // Matrix as in Beyn, section 4.11
   6 int M_function(complex double *target, const size_t m, const complex double z, void *no_params) {
   7   complex double d =  2*m - 4*z / (6*m);
   8   complex double od =  -((double)m) - z / (6*m);
   9
  10   memset(target, 0, m*m*sizeof(complex double));
  11   for (int i = 0; i < m; ++i) {
  12     target[i*m + i] = d;
  13     if(i > 0) target[i*m + i-1] = od;
  14     if(i < m - 1) target[i*m + i+1] = od;
  15   }
  16   target[m*(m-1) + m-1] = d/2 + z/(z-1);
  17
  18   return 0;
  19 }
  20
  21 int main() {
  22   complex double z0 = 150+2*I;
  23   double Rx = 148, Ry = 148;
  24   int L = 10, N = 50, dim = 400;
  25   beyn_contour_t *contour = beyn_contour_ellipse(z0, Rx, Ry, N);
  26
  27   beyn_result_t *result =
  28     beyn_solve(dim, L, M_function, NULL /*M_inv_Vhat_function*/, NULL /*params*/,
  29       contour, 1e-4, 1, 1e-4);
  30   printf("Found %zd eigenvalues:\n", result->neig);
  31   for (size_t i = 0; i < result->neig; ++i) {
  32     complex double eig = result->eigval[i];
  33     printf("%zd: %g%+gj\n", i, creal(eig), cimag(eig));
  34   }
  35   free(contour);
  36   beyn_result_free(result);
  37   return 0;
  38 }
  39
  40