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Separate Ewald parameter for different frequencies 

Former-commit-id: 0b9129fda0224411c2a1d8372fe715db4e071ecd
This commit is contained in:
Marek Nečada 2020-04-22 16:18:16 +03:00
parent 83e76b1f95
commit 8ed4bdb683
4 changed files with 59 additions and 16 deletions
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28
qpms/qpms_c.pyx
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@ -568,7 +568,10 @@ cdef class ScatteringSystem:
return None
property eta:
"""Ewald parameter η"""
"""Ewald parameter η (only relevant for periodic systems)
This is the default value that will be copied into
_ScatteringSystemAtOmega by __call__"""
def __get__(self):
self.check_s()
if self.lattice_dimension:
@ -723,7 +726,7 @@ cdef class ScatteringSystem:
self.s, iri, 0)
return target_np
def translation_matrix_full(self, cdouble wavenumber, blochvector = None, J = QPMS_HANKEL_PLUS):
def translation_matrix_full(self, cdouble wavenumber, blochvector = None, J = QPMS_HANKEL_PLUS, double eta = 0):
"""Constructs full translation matrix of a scattering system.
This method enables to use any wave number for the background medium ignoring the
@ -741,6 +744,11 @@ cdef class ScatteringSystem:
J : BesselType
Optionally, one can replace Hankel functions of the first kind with different
Bessel functions.
eta : float
Ewald parameter η, only relevant for periodic lattices;
if set to 0 (default), the actual value is determined
automatically.
See Also
--------
@ -763,7 +771,7 @@ cdef class ScatteringSystem:
raise NotImplementedError("Translation operators based on other than Hankel+ functions not supperted in periodic systems")
blochvector_c = {'x': blochvector[0], 'y': blochvector[1], 'z': blochvector[2]}
with pgsl_ignore_error(15):
qpms_scatsys_periodic_build_translation_matrix_full(&target_view[0][0], self.s, wavenumber, &blochvector_c)
qpms_scatsys_periodic_build_translation_matrix_full(&target_view[0][0], self.s, wavenumber, &blochvector_c, eta)
return target
def translation_matrix_packed(self, cdouble wavenumber, qpms_iri_t iri, J = QPMS_HANKEL_PLUS):
@ -1025,6 +1033,20 @@ cdef class _ScatteringSystemAtOmega:
def __get__(self): return self.ss_pyref.nirreps
property wavenumber:
def __get__(self): return self.ssw[0].wavenumber
property eta:
"""Ewald parameter η (only relevant for periodic systems)"""
def __get__(self):
self.check_s()
if self.lattice_dimension:
return self.ssw[0].eta
else:
return None
def __set__(self, double eta):
self.check_s()
if self.lattice_dimension:
self.ssw[0].eta = eta
else:
raise AttributeError("Cannot set Ewald parameter for finite system") # different exception?
def modeproblem_matrix_full(self, k=None):

3
qpms/qpms_cdefs.pxd
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@ -630,6 +630,7 @@ cdef extern from "scatsystem.h":
cdouble omega
qpms_epsmu_t medium
cdouble wavenumber
double eta
qpms_scatsys_at_omega_t *qpms_scatsys_apply_symmetry(const qpms_scatsys_t *orig, const qpms_finite_group_t *sym,
cdouble omega, const qpms_tolerance_spec_t *tol)
qpms_scatsys_at_omega_t *qpms_scatsys_at_omega(const qpms_scatsys_t *ss, cdouble omega)
@ -688,7 +689,7 @@ cdef extern from "scatsystem.h":
const qpms_scatsys_at_omega_t *ssw
double k[3]
cdouble *qpms_scatsyswk_build_modeproblem_matrix_full(cdouble *target, const qpms_scatsys_at_omega_k_t *sswk)
cdouble *qpms_scatsys_periodic_build_translation_matrix_full(cdouble *target, const qpms_scatsys_t *ss, cdouble wavenumber, const cart3_t *wavevector)
cdouble *qpms_scatsys_periodic_build_translation_matrix_full(cdouble *target, const qpms_scatsys_t *ss, cdouble wavenumber, const cart3_t *wavevector, double eta)
qpms_ss_LU qpms_scatsyswk_build_modeproblem_matrix_full_LU(cdouble *target, int *target_piv, const qpms_scatsys_at_omega_k_t *sswk)
beyn_result_t *qpms_scatsys_periodic_find_eigenmodes(const qpms_scatsys_t *ss, const double *k,
cdouble omega_centre, double omega_rr, double omega_ri, size_t contour_npoints,

33
qpms/scatsystem.c
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@ -59,6 +59,13 @@ static inline void qpms_ss_ensure_nonperiodic_a(const qpms_scatsys_t *ss, const
QPMS_ENSURE(ss->lattice_dimension == 0, "This method is applicable only to nonperiodic systems. Use %s instead.", s);
}
// Adjust Ewald parameter to avoid high-frequency breakdown;
// TODO make this actually do something (other than just copying ss's eta.)
static inline double ss_adjusted_eta(const qpms_scatsys_t *ss, complex double omega) {
qpms_ss_ensure_periodic(ss);
return ss->per.eta;
}
// ------------ Stupid implementation of qpms_scatsys_apply_symmetry() -------------
#define MIN(x,y) (((x)<(y))?(x):(y))
@ -541,6 +548,9 @@ qpms_scatsys_at_omega_t *qpms_scatsys_apply_symmetry(const qpms_scatsys_t *orig,
}
ss->c = qpms_trans_calculator_init(lMax, normalisation);
ssw->eta = ss->lattice_dimension ? ss_adjusted_eta(ss, omega) : NAN;
return ssw;
}
@ -594,6 +604,7 @@ qpms_scatsys_at_omega_t *qpms_scatsys_at_omega(const qpms_scatsys_t *ss,
ssw->ss = ss;
ssw->medium = qpms_epsmu_generator_eval(ss->medium, omega);
ssw->wavenumber = qpms_wavenumber(omega, ssw->medium);
ssw->eta = ss->lattice_dimension ? ss_adjusted_eta(ss, omega) : NAN;
QPMS_CRASHING_CALLOC(ssw->tm, ss->tm_count, sizeof(*ssw->tm));
qpms_tmatrix_t **tmatrices_preop;
QPMS_CRASHING_CALLOC(tmatrices_preop, ss->tmg_count, sizeof(*tmatrices_preop));
@ -1156,7 +1167,7 @@ complex double *qpms_scatsyswk_build_translation_matrix_full(
const qpms_scatsys_t *ss = ssw->ss;
qpms_ss_ensure_periodic(ss);
const cart3_t k_cart3 = cart3_from_double_array(sswk->k);
return qpms_scatsys_periodic_build_translation_matrix_full(target, ss, wavenumber, &k_cart3);
return qpms_scatsys_periodic_build_translation_matrix_full(target, ss, wavenumber, &k_cart3, ssw->eta);
}
complex double *qpms_scatsys_build_translation_matrix_e_full(
@ -1201,17 +1212,17 @@ complex double *qpms_scatsys_build_translation_matrix_e_full(
static inline int qpms_ss_ppair_W32xy(const qpms_scatsys_t *ss,
qpms_ss_pi_t pdest, qpms_ss_pi_t psrc, complex double wavenumber, const cart2_t kvector,
complex double *target, const ptrdiff_t deststride, const ptrdiff_t srcstride,
qpms_ewald_part parts) {
qpms_ewald_part parts, double eta) {
const qpms_vswf_set_spec_t *srcspec = qpms_ss_bspec_pi(ss, psrc);
const qpms_vswf_set_spec_t *destspec = qpms_ss_bspec_pi(ss, pdest);
// This might be a bit arbitrary, roughly "copied" from Unitcell constructor. TODO review.
const double maxR = sqrt(ss->per.unitcell_volume) * 32;
const double maxK = 1024 * 2 * M_PI / maxR;
const double maxR = sqrt(ss->per.unitcell_volume) * 64;
const double maxK = 2048 * 2 * M_PI / maxR;
return qpms_trans_calculator_get_trans_array_e32_e(ss->c,
target, NULL /*err*/, destspec, deststride, srcspec, srcstride,
ss->per.eta, wavenumber,
eta, wavenumber,
cart3xy2cart2(ss->per.lattice_basis[0]), cart3xy2cart2(ss->per.lattice_basis[1]),
kvector,
cart2_substract(cart3xy2cart2(ss->p[pdest].pos), cart3xy2cart2(ss->p[psrc].pos)),
@ -1221,21 +1232,23 @@ static inline int qpms_ss_ppair_W32xy(const qpms_scatsys_t *ss,
static inline int qpms_ss_ppair_W(const qpms_scatsys_t *ss,
qpms_ss_pi_t pdest, qpms_ss_pi_t psrc, complex double wavenumber, const double wavevector[],
complex double *target, const ptrdiff_t deststride, const ptrdiff_t srcstride,
qpms_ewald_part parts) {
qpms_ewald_part parts, double eta) {
if(ss->lattice_dimension == 2 && // Currently, we can only the xy-plane
!ss->per.lattice_basis[0].z && !ss->per.lattice_basis[1].z &&
!wavevector[2])
return qpms_ss_ppair_W32xy(ss, pdest, psrc, wavenumber, cart2_from_double_array(wavevector),
target, deststride, srcstride, parts);
target, deststride, srcstride, parts, eta);
else
QPMS_NOT_IMPLEMENTED("Only 2D xy-lattices currently supported");
}
complex double *qpms_scatsys_periodic_build_translation_matrix_full(
complex double *target, const qpms_scatsys_t *ss,
complex double wavenumber, const cart3_t *wavevector) {
complex double wavenumber, const cart3_t *wavevector, double eta) {
QPMS_UNTESTED;
qpms_ss_ensure_periodic(ss);
if (eta == 0 || isnan(eta))
eta = ss->per.eta;
const size_t full_len = ss->fecv_size;
if(!target)
QPMS_CRASHING_MALLOC(target, SQ(full_len) * sizeof(complex double));
@ -1248,7 +1261,7 @@ complex double *qpms_scatsys_periodic_build_translation_matrix_full(
for (qpms_ss_pi_t ps = 0; ps < ss->p_count; ++ps) {
QPMS_ENSURE_SUCCESS(qpms_ss_ppair_W32xy(ss, pd, ps, wavenumber, cart3xy2cart2(*wavevector),
target + deststride * ss->fecv_pstarts[pd] + srcstride * ss->fecv_pstarts[ps],
deststride, srcstride, QPMS_EWALD_FULL));
deststride, srcstride, QPMS_EWALD_FULL, eta));
}
} else
QPMS_NOT_IMPLEMENTED("Only 2D xy-lattices currently supported");
@ -1294,7 +1307,7 @@ static inline complex double *qpms_scatsysw_scatsyswk_build_modeproblem_matrix_f
} else { // periodic case
QPMS_ENSURE_SUCCESS(qpms_ss_ppair_W(ss, piR, piC, wavenumber, k,
tmp /*target*/, bspecC->n /*deststride*/, 1 /*srcstride*/,
QPMS_EWALD_FULL));
QPMS_EWALD_FULL, ssw->eta));
}
cblas_zgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans,

11
qpms/scatsystem.h
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@ -147,7 +147,12 @@ typedef struct qpms_scatsys_periodic_info_t {
*/
double unitcell_volume;
/// Ewald parameter \f$ \eta \f$.
/// Default Ewald parameter \f$ \eta \f$.
/** Normally, this just gets copied into qpms_scatsys_at_omega_t,
* which is then used in the Ewald sums.
* However, for higher frequencies it must be adjusted to avoid
* numerical instability.
*/
double eta;
} qpms_scatsys_periodic_info_t;
@ -241,6 +246,7 @@ typedef struct qpms_scatsys_at_omega_t {
complex double omega; ///< Angular frequency
qpms_epsmu_t medium; ///< Background medium optical properties at the given frequency
complex double wavenumber; ///< Background medium wave number
double eta; ///< Ewald parameter \f$ \eta \f$.
} qpms_scatsys_at_omega_t;
@ -501,7 +507,8 @@ complex double *qpms_scatsys_periodic_build_translation_matrix_full(
complex double *target,
const qpms_scatsys_t *ss,
complex double wavenumber, ///< Wave number to use in the translation matrix.
const cart3_t *wavevector ///< Wavevector / pseudomomentum in cartesian coordinates.
const cart3_t *wavevector, ///< Wavevector / pseudomomentum in cartesian coordinates.
double eta ///< Ewald parameter eta. Pass 0 or NaN to use the default value in \a ss.
);
/// Global translation matrix.