int igraph_vector_complex_create(igraph_vector_complex_t *v,
const igraph_vector_t *real,
const igraph_vector_t *imag) {
int i, n=igraph_vector_size(real);
if (n != igraph_vector_size(imag)) {
IGRAPH_ERROR("Real and imag vector sizes don't match", IGRAPH_EINVAL);
}
IGRAPH_CHECK(igraph_vector_complex_init(v, n));
/* FINALLY not needed */
for (i=0; i<n; i++) {
VECTOR(*v)[i] = igraph_complex(VECTOR(*real)[i], VECTOR(*imag)[i]);
}
return 0;
}
int igraph_i_eigen_matrix_lapack_reorder(const igraph_vector_t *real,
const igraph_vector_t *imag,
const igraph_matrix_t *compressed,
const igraph_eigen_which_t *which,
igraph_vector_complex_t *values,
igraph_matrix_complex_t *vectors) {
igraph_vector_int_t idx;
igraph_vector_t mag;
igraph_bool_t hasmag=0;
int nev=(int) igraph_vector_size(real);
int howmany=0, start=0;
int i;
igraph_i_eigen_matrix_lapack_cmp_t cmpfunc=0;
igraph_i_eml_cmp_t vextra = { &mag, real, imag };
void *extra=&vextra;
IGRAPH_CHECK(igraph_vector_int_init(&idx, nev));
IGRAPH_FINALLY(igraph_vector_int_destroy, &idx);
switch (which->pos) {
case IGRAPH_EIGEN_LM:
INITMAG();
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_lm;
howmany=which->howmany;
break;
case IGRAPH_EIGEN_ALL:
INITMAG();
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_sm;
howmany=nev;
break;
case IGRAPH_EIGEN_SM:
INITMAG();
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_sm;
howmany=which->howmany;
break;
case IGRAPH_EIGEN_LR:
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_lr;
howmany=which->howmany;
break;
case IGRAPH_EIGEN_SR:
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_sr;
howmany=which->howmany;
break;
case IGRAPH_EIGEN_SELECT:
INITMAG();
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_sm;
start=which->il-1;
howmany=which->iu - which->il + 1;
break;
case IGRAPH_EIGEN_LI:
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_li;
howmany=which->howmany;
break;
case IGRAPH_EIGEN_SI:
cmpfunc=igraph_i_eigen_matrix_lapack_cmp_si;
howmany=which->howmany;
break;
case IGRAPH_EIGEN_INTERVAL:
case IGRAPH_EIGEN_BE:
default:
IGRAPH_ERROR("Unimplemented eigenvalue ordering", IGRAPH_UNIMPLEMENTED);
break;
}
for (i=0; i<nev; i++) {
VECTOR(idx)[i] = i;
}
igraph_qsort_r(VECTOR(idx), (size_t) nev, sizeof(VECTOR(idx)[0]), extra,
cmpfunc);
if (hasmag) {
igraph_vector_destroy(&mag);
IGRAPH_FINALLY_CLEAN(1);
}
if (values) {
IGRAPH_CHECK(igraph_vector_complex_resize(values, howmany));
for (i=0; i<howmany; i++) {
int x=VECTOR(idx)[start+i];
VECTOR(*values)[i] = igraph_complex(VECTOR(*real)[x],
VECTOR(*imag)[x]);
}
}
if (vectors) {
int n=(int) igraph_matrix_nrow(compressed);
IGRAPH_CHECK(igraph_matrix_complex_resize(vectors, n, howmany));
for (i=0; i<howmany; i++) {
int j, x=VECTOR(idx)[start+i];
if (VECTOR(*imag)[x] == 0) {
/* real eigenvalue */
for (j=0; j<n; j++) {
MATRIX(*vectors, j, i) = igraph_complex(MATRIX(*compressed, j, x),
0.0);
}
} else {
/* complex eigenvalue */
int neg=1, co=0;
if (VECTOR(*imag)[x] < 0) { neg=-1; co=1; }
for (j=0; j<n; j++) {
MATRIX(*vectors, j, i) =
igraph_complex(MATRIX(*compressed, j, x-co),
neg * MATRIX(*compressed, j, x+1-co));
}
}
}
}
igraph_vector_int_destroy(&idx);
IGRAPH_FINALLY_CLEAN(1);
return 0;
}
