41 lines
1.1 KiB
C
41 lines
1.1 KiB
C
#include <qpms/beyn.h>
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#include <stdio.h>
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#include <string.h>
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// Matrix as in Beyn, section 4.11
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int M_function(complex double *target, const size_t m, const complex double z, void *no_params) {
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complex double d = 2*m - 4*z / (6*m);
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complex double od = -((double)m) - z / (6*m);
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memset(target, 0, m*m*sizeof(complex double));
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for (int i = 0; i < m; ++i) {
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target[i*m + i] = d;
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if(i > 0) target[i*m + i-1] = od;
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if(i < m - 1) target[i*m + i+1] = od;
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}
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target[m*(m-1) + m-1] = d/2 + z/(z-1);
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return 0;
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}
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int main() {
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complex double z0 = 150+2*I;
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double Rx = 148, Ry = 148;
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int L = 10, N = 50, dim = 400;
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beyn_contour_t *contour = beyn_contour_ellipse(z0, Rx, Ry, N);
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beyn_result_t *result =
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beyn_solve(dim, L, M_function, NULL /*M_inv_Vhat_function*/, NULL /*params*/,
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contour, 1e-4, 1e-4);
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printf("Found %zd eigenvalues:\n", result->neig);
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for (size_t i = 0; i < result->neig; ++i) {
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complex double eig = result->eigval[i];
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printf("%zd: %g%+gj\n", i, creal(eig), cimag(eig));
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}
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free(contour);
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beyn_result_free(result);
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return 0;
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}
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