Adjust eta for each (omega, k) pair to prevent hi-freq breakdown.

This effectively reverts 0b9129, because it does not make to define
Ewald parameter for just each frequency after all...


Former-commit-id: 6a3df5ecc1eecd6c120a74c70df5b747d593aae3
This commit is contained in:
Marek Nečada 2020-04-26 17:10:47 +03:00
parent 999dc7f72e
commit 14a5c32202
4 changed files with 48 additions and 35 deletions

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@ -964,6 +964,13 @@ cdef class _ScatteringSystemAtOmegaK:
cdef qpms_scatsys_at_omega_k_t *rawpointer(self):
return &self.sswk
property eta:
"""Ewald parameter η"""
def __get__(self):
return self.sswk.eta
def __set__(self, double eta):
self.sswk.eta = eta
cdef class _ScatteringSystemAtOmega:
'''
Wrapper over the C qpms_scatsys_at_omega_t structure
@ -1021,6 +1028,7 @@ cdef class _ScatteringSystemAtOmega:
sswk.sswk.k[0] = k[0]
sswk.sswk.k[1] = k[1]
sswk.sswk.k[2] = k[2]
sswk.eta = qpms_ss_adjusted_eta(self.ssw[0].ss, self.ssw[0].wavenumber, sswk.sswk.k)
return sswk
property fecv_size:
@ -1033,20 +1041,6 @@ 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):

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@ -630,7 +630,6 @@ 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)
@ -688,6 +687,7 @@ cdef extern from "scatsystem.h":
struct qpms_scatsys_at_omega_k_t:
const qpms_scatsys_at_omega_t *ssw
double k[3]
double eta
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, 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)
@ -703,6 +703,8 @@ cdef extern from "scatsystem.h":
const cdouble *f_excitation_vector_full, cart3_t where)
ccart3_t qpms_scatsysw_scattered_E__alt(const qpms_scatsys_at_omega_t *ssw, qpms_bessel_t btyp,
const cdouble *f_excitation_vector_full, cart3_t where)
double qpms_ss_adjusted_eta(const qpms_scatsys_t *ss, cdouble wavenumber, const double *wavevector);
cdef extern from "ewald.h":
struct qpms_csf_result:

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@ -23,6 +23,7 @@
#include "kahansum.h"
#include "tolerances.h"
#include "beyn.h"
#include "tiny_inlines.h"
#ifdef QPMS_SCATSYSTEM_USE_OWN_BLAS
#include "qpmsblas.h"
@ -31,11 +32,15 @@
#define SERIAL_ZGEMM cblas_zgemm
#endif
#define SQ(x) ((x)*(x))
#define QPMS_SCATSYS_LEN_RTOL 1e-13
#define QPMS_SCATSYS_TMATRIX_ATOL 1e-12
#define QPMS_SCATSYS_TMATRIX_RTOL 1e-12
// This is used in adjustment of Ewald parameter to avoid high frequency breakdown.
// Very roughly, the value of 16 should lead to allowing terms containing incomplete Gamma
// functions with magnitudes around exp(16) == 8.9e6
static const double QPMS_SCATSYS_EWALD_MAX_EXPONENT = 16.;
long qpms_scatsystem_nthreads_default = 4;
long qpms_scatsystem_nthreads_override = 0;
@ -59,18 +64,23 @@ 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) {
// Adjust Ewald parameter to avoid high-frequency breakdown
double qpms_ss_adjusted_eta(const qpms_scatsys_t *ss, complex double wavenumber, const double k[3]) {
qpms_ss_ensure_periodic(ss);
return ss->per.eta;
const double eta_default = ss->per.eta;
// FIXME here we silently assume that k lies in the first Brillioun zone, we should ensure that.
const double k2 = k[0]*k[0] + k[1]*k[1] + k[2] * k[2];
const double kappa2 = SQ(cabs(wavenumber)); // maybe creal would be enough
if(kappa2 < k2) // This should happen only for pretty low frequencies
return eta_default;
const qpms_l_t maxj = ss->c->lMax; // Based on ewald.c:301, note that VSWF (c's) lMax is already half of corresponding translation matrix Ewald factors' (c->e3c's) lMax
const double mina = 0.5 * (ss->lattice_dimension - 1) - maxj; // minimum incomplete Gamma first argument, based on ewald.c:301; CHECKME whether this is fine also for 3D lattice
const double eta_min = sqrt(fabs((kappa2 - k2) * (mina - 1.) / QPMS_SCATSYS_EWALD_MAX_EXPONENT));
return MAX(eta_default, eta_min);
}
// ------------ Stupid implementation of qpms_scatsys_apply_symmetry() -------------
#define MIN(x,y) (((x)<(y))?(x):(y))
#define MAX(x,y) (((x)>(y))?(x):(y))
// The following functions are just to make qpms_scatsys_apply_symmetry more readable.
// They are not to be used elsewhere, as they do not perform any array capacity checks etc.
@ -549,8 +559,6 @@ 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;
}
@ -604,7 +612,6 @@ 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));
@ -1167,7 +1174,7 @@ 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, ssw->eta);
return qpms_scatsys_periodic_build_translation_matrix_full(target, ss, wavenumber, &k_cart3, sswk->eta);
}
complex double *qpms_scatsys_build_translation_matrix_e_full(
@ -1247,8 +1254,12 @@ complex double *qpms_scatsys_periodic_build_translation_matrix_full(
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;
if (eta == 0 || isnan(eta)) {
double tmp[3];
cart3_to_double_array(tmp, *wavevector);
eta = qpms_ss_adjusted_eta(ss, wavenumber, tmp);
}
const size_t full_len = ss->fecv_size;
if(!target)
QPMS_CRASHING_MALLOC(target, SQ(full_len) * sizeof(complex double));
@ -1273,7 +1284,8 @@ static inline complex double *qpms_scatsysw_scatsyswk_build_modeproblem_matrix_f
/// Target memory with capacity for ss->fecv_size**2 elements. If NULL, new will be allocated.
complex double *target,
const qpms_scatsys_at_omega_t *ssw,
const double k[] // NULL if non-periodic
const double k[], // NULL if non-periodic
const double eta // ignored if non-periodic
)
{
const complex double wavenumber = ssw->wavenumber;
@ -1307,7 +1319,7 @@ 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, ssw->eta));
QPMS_EWALD_FULL, eta));
}
cblas_zgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans,
@ -1334,14 +1346,14 @@ complex double *qpms_scatsysw_build_modeproblem_matrix_full(
complex double *target, const qpms_scatsys_at_omega_t *ssw) {
qpms_ss_ensure_nonperiodic_a(ssw->ss, "qpms_scatsyswk_build_modeproblem_matrix_full()");
return qpms_scatsysw_scatsyswk_build_modeproblem_matrix_full(
target, ssw, NULL);
target, ssw, NULL, NAN);
}
complex double *qpms_scatsyswk_build_modeproblem_matrix_full(
complex double *target, const qpms_scatsys_at_omega_k_t *sswk)
{
qpms_ss_ensure_periodic_a(sswk->ssw->ss, "qpms_scatsysw_build_modeproblem_matrix_full()");
return qpms_scatsysw_scatsyswk_build_modeproblem_matrix_full(target, sswk->ssw, sswk->k);
return qpms_scatsysw_scatsyswk_build_modeproblem_matrix_full(target, sswk->ssw, sswk->k, sswk->eta);
}
@ -2246,7 +2258,8 @@ static int qpms_scatsys_periodic_eval_Beyn_ImTW(complex double *target,
QPMS_ENSURE(ssw != NULL, "qpms_scatsys_at_omega() returned NULL");
qpms_scatsys_at_omega_k_t sswk = {
.ssw = ssw,
.k = {p->k[0], p->k[1], p->k[2]}
.k = {p->k[0], p->k[1], p->k[2]},
.eta = qpms_ss_adjusted_eta(p->ss, ssw->wavenumber, p->k)
};
QPMS_ASSERT(m == p->ss->fecv_size);
QPMS_ENSURE(NULL !=

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@ -246,7 +246,6 @@ 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$.
} qpms_scatsys_at_omega_t;
@ -489,6 +488,7 @@ complex double *qpms_scatsys_scatter_solve(
typedef struct qpms_scatsys_at_omega_k_t {
const qpms_scatsys_at_omega_t *ssw;
double k[3]; ///< The k-vector's cartesian coordinates.
double eta; ///< Ewald parameter η.
} qpms_scatsys_at_omega_k_t;
/// Creates the full \f$ (I - WS) \f$ matrix of the periodic scattering system.
@ -769,6 +769,10 @@ ccart3_t qpms_scatsysw_scattered_E__alt(
cart3_t evalpoint ///< A point \f$ \vect r \f$, at which the field is evaluated.
);
/// Adjusted Ewadl parameter to avoid high-frequency breakdown.
// TODO DOC
double qpms_ss_adjusted_eta(const qpms_scatsys_t *ss, complex double wavenumber, const double wavevector[3]);
#if 0
/** Evaluates partial scattered fields (corresponding to a given irrep-reduced excitation vector)
* at a given point.