284 lines
10 KiB
C
284 lines
10 KiB
C
/*! \file normalisation.h
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* \brief Convention-dependent coefficients for VSWFs.
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*
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* See also @ref qpms_normalisation_t and @ref vswf_conventions.
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*/
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#ifndef NORMALISATION_H
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#define NORMALISATION_H
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#include "qpms_types.h"
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#include "qpms_error.h"
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#include <math.h>
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#include <complex.h>
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#include "indexing.h"
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/// Returns the (real positive) common norm factor of a given normalisation compared to the reference convention.
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/** Does NOT perform the inversion if QPMS_NORMALISATION_INVERSE is set. */
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static inline double qpms_normalisation_normfactor(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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switch (norm & QPMS_NORMALISATION_NORM_BITS) {
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case QPMS_NORMALISATION_NORM_POWER:
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return 1;
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case QPMS_NORMALISATION_NORM_SPHARM:
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return sqrt(l*(l+1));
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case QPMS_NORMALISATION_NORM_NONE: // TODO more precision
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return sqrt(l*(l+1) * 4*M_PI / (2*l+1)) *
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exp(0.5*(lgamma(l+m+1) - lgamma(l-m+1)));
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default:
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QPMS_WTF;
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}
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}
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/// Returns the factors of a magnetic basis VSWF of a given convention compared to the reference convention.
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/**
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* This version ignores the Condon-Shortley phase bit (perhaps because the Condon-Shortley
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* phase is already taken into account in a `gsl_sf_legendre_*_e()` call.)
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*/
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static inline complex double qpms_normalisation_factor_M_noCS(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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complex double fac = qpms_normalisation_normfactor(norm, l, m);
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if (norm & QPMS_NORMALISATION_M_MINUS) fac *= -1;
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if (norm & QPMS_NORMALISATION_M_I) fac *= I;
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if (norm & QPMS_NORMALISATION_INVERSE) fac = 1/fac;
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return fac;
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}
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/// Returns the factors of a magnetic basis VSWF of a given convention compared to the reference convention.
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/**
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* This version takes into account the Condon-Shortley phase bit.
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* Do not use if the C.-S. has already been taken into account e.g. in
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* a `gsl_sf_legendre_*_e()` call.
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*/
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static inline complex double qpms_normalisation_factor_M(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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complex double fac = qpms_normalisation_factor_M_noCS(norm, l, m);
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return ((norm & QPMS_NORMALISATION_CSPHASE) && (m % 2)) ? -fac : fac;
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}
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/// Returns the factors of a electric basis VSWF of a given convention compared to the reference convention.
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/**
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* This version ignores the Condon-Shortley phase bit (perhaps because the Condon-Shortley
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* phase is already taken into account in a `gsl_sf_legendre_*_e()` call.)
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*/
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static inline complex double qpms_normalisation_factor_N_noCS(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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complex double fac = qpms_normalisation_normfactor(norm, l, m);
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if (norm & QPMS_NORMALISATION_N_MINUS) fac *= -1;
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if (norm & QPMS_NORMALISATION_N_I) fac *= I;
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if (norm & QPMS_NORMALISATION_INVERSE) fac = 1/fac;
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return fac;
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}
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/// Returns the factors of a electric basis VSWF of a given convention compared to the reference convention.
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/**
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* This version takes into account the Condon-Shortley phase bit.
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* Do not use if the C.-S. has already been taken into account e.g. in
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* a `gsl_sf_legendre_*_e()` call.
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*/
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static inline complex double qpms_normalisation_factor_N(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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complex double fac = qpms_normalisation_factor_N_noCS(norm, l, m);
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return ((norm & QPMS_NORMALISATION_CSPHASE) && (m % 2)) ? -fac : fac;
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}
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/// Returns the factors of a electric basis VSWF divided by the factor of a magnetic VWFS of a given convention, compared to the reference one.
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static inline complex double qpms_normalisation_factor_N_M(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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return qpms_normalisation_factor_N_noCS(norm, l, m)
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/ qpms_normalisation_factor_M_noCS(norm, l, m);
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}
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/// Returns the factors of a longitudinal basis VSWF of a given convention compared to the reference convention.
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/**
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* This version ignores the Condon-Shortley phase bit (perhaps because the Condon-Shortley
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* phase is already taken into account in a `gsl_sf_legendre_*_e()` call.)
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*/
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static inline complex double qpms_normalisation_factor_L_noCS(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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complex double fac = qpms_normalisation_normfactor(norm, l, m);
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if (norm & QPMS_NORMALISATION_L_MINUS) fac *= -1;
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if (norm & QPMS_NORMALISATION_L_I) fac *= I;
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if (norm & QPMS_NORMALISATION_INVERSE) fac = 1/fac;
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return fac;
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}
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/// Returns the factors of a longitudinal basis VSWF of a given convention compared to the reference convention.
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/**
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* This version takes into account the Condon-Shortley phase bit.
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* Do not use if the C.-S. has already been taken into account e.g. in
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* a `gsl_sf_legendre_*_e()` call.
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*/
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static inline complex double qpms_normalisation_factor_L(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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complex double fac = qpms_normalisation_factor_L_noCS(norm, l, m);
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return ((norm & QPMS_NORMALISATION_CSPHASE) && (m % 2)) ? -fac : fac;
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}
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/// Returns the factors of a basis VSWF of a given convention compared to the reference convention.
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static inline complex double qpms_normalisation_factor_uvswfi(const qpms_normalisation_t norm, qpms_uvswfi_t ui) {
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qpms_vswf_type_t t; qpms_m_t m; qpms_l_t l;
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qpms_uvswfi2tmn(ui, &t, &m, &l);
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switch(t) {
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case QPMS_VSWF_MAGNETIC:
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return qpms_normalisation_factor_M(norm, l, m);
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case QPMS_VSWF_ELECTRIC:
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return qpms_normalisation_factor_N(norm, l, m);
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case QPMS_VSWF_LONGITUDINAL:
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return qpms_normalisation_factor_L(norm, l, m);
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default:
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QPMS_WTF;
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}
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}
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/// Returns normalisation flags corresponding to the dual spherical harmonics / waves.
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/**
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* This reverses the normalisation factors returned by qpms_normalisation_factor_*
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* and conjugates the asimuthal part for complex spherical harmonics,
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* \f$ e^{\pm im\phi} \leftrightarrow e^{\mp im\phi} \f$.
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*/
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static inline qpms_normalisation_t qpms_normalisation_dual(qpms_normalisation_t norm) {
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norm ^= QPMS_NORMALISATION_INVERSE;
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if (!(norm & QPMS_NORMALISATION_SPHARM_REAL))
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norm ^= QPMS_NORMALISATION_REVERSE_AZIMUTHAL_PHASE;
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return norm;
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}
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/// Returns the asimuthal part of a spherical harmonic.
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/** Returns \f[ e^{im\phi} \f] for standard complex spherical harmonics,
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* \f[ e^{-im\phi \f] for complex spherical harmonics
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* and QPMS_NORMALISATION_REVERSE_AZIMUTHAL_PHASE set.
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*
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* For real spherical harmonics, this gives
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* \f[
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* \sqrt{2}\cos{m \phi} \quad \mbox{if } m>0, \\
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* \sqrt{2}\sin{m \phi} \quad \mbox{if } m<0, \\
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* 0 \quad \mbox{if } m>0. \\
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* \f]
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*/
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static inline complex double qpms_spharm_azimuthal_part(qpms_normalisation_t norm, qpms_m_t m, double phi) {
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switch(norm & (QPMS_NORMALISATION_REVERSE_AZIMUTHAL_PHASE | QPMS_NORMALISATION_SPHARM_REAL)) {
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case 0:
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return cexp(I*m*phi);
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case QPMS_NORMALISATION_REVERSE_AZIMUTHAL_PHASE:
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return cexp(-I*m*phi);
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case QPMS_NORMALISATION_SPHARM_REAL:
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if (m > 0) return M_SQRT2 * cos(m*phi);
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else if (m < 0) return M_SQRT2 * sin(m*phi);
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else return 1.;
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default:
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QPMS_WTF;
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}
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}
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/// Returns derivative of the asimuthal part of a spherical harmonic divided by \a m.
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/**
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*
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* This is used to evaluate the VSWFs together with the \a pi member array of the
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* qpms_pitau_t structure.
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*
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* Returns \f[ i e^{im\phi} \f] for standard complex spherical harmonics,
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* \f[-i e^{-i\phi \f] for complex spherical harmonics
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* and QPMS_NORMALISATION_REVERSE_AZIMUTHAL_PHASE set.
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*
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* For real spherical harmonics, this gives
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* \f[
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* -\sqrt{2}\sin{m \phi} \quad \mbox{if } m>0, \\
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* \sqrt{2}\cos{m \phi} \quad \mbox{if } m<0, \\
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* -1 \quad \mbox{if } \mbox{if }m=0. \\
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* \f]
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*
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* (The value returned for \f$ m = 0 \f$ should not actually be used for
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* anything except for multiplying by zero.)
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*
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*
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*/
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static inline complex double qpms_spharm_azimuthal_part_derivative_div_m(qpms_normalisation_t norm, qpms_m_t m, double phi) {
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if(m==0) return 0;
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switch(norm & (QPMS_NORMALISATION_REVERSE_AZIMUTHAL_PHASE | QPMS_NORMALISATION_SPHARM_REAL)) {
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case 0:
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return I*cexp(I*m*phi);
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case QPMS_NORMALISATION_REVERSE_AZIMUTHAL_PHASE:
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return -I*cexp(-I*m*phi);
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case QPMS_NORMALISATION_SPHARM_REAL:
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if (m > 0) return -M_SQRT2 * sin(m*phi);
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else if (m < 0) return M_SQRT2 * cos(m*phi);
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else return -1;
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default:
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QPMS_WTF;
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}
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}
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#if 0 // legacy code moved from qpms_types.h. TODO cleanup
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/// Returns the normalisation convention code without the Condon-Shortley phase.
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static inline int qpms_normalisation_t_normonly(qpms_normalisation_t norm) {
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return norm & (~QPMS_NORMALISATION_T_CSBIT);
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}
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/* Normalisation of the spherical waves is now scattered in at least three different files:
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* here, we have the norm in terms of radiated power of outgoing wave.
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* In file legendre.c, function qpms_pitau_get determines the norm used in the vswf.c
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* spherical vector wave norms. The "dual" waves in vswf.c use the ..._abssquare function below.
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* In file translations.c, the normalisations are again set by hand using the normfac and lognormfac
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* functions.
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*/
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#include <math.h>
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#include <assert.h>
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// relative to QPMS_NORMALISATION_KRISTENSSON_CS, i.e.
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// P_l^m[normtype] = P_l^m[Kristensson]
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static inline double qpms_normalisation_t_factor(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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int csphase = qpms_normalisation_t_csphase(norm);
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norm = qpms_normalisation_t_normonly(norm);
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double factor;
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switch (norm) {
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case QPMS_NORMALISATION_KRISTENSSON:
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factor = 1.;
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break;
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case QPMS_NORMALISATION_TAYLOR:
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factor = sqrt(l*(l+1));
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break;
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case QPMS_NORMALISATION_NONE:
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factor = sqrt(l*(l+1) * 4 * M_PI / (2*l+1) * exp(lgamma(l+m+1)-lgamma(l-m+1)));
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break;
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#ifdef USE_XU_ANTINORMALISATION // broken probably in legendre.c
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case QPMS_NORMALISATION_XU:
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factor = sqrt(4 * M_PI) / (2*l+1) * exp(lgamma(l+m+1)-lgamma(l-m+1));
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break;
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#endif
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default:
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assert(0);
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}
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factor *= (m%2)?(-csphase):1;
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return factor;
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}
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// TODO move elsewhere
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static inline double qpms_normalisation_t_factor_abssquare(qpms_normalisation_t norm, qpms_l_t l, qpms_m_t m) {
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norm = qpms_normalisation_t_normonly(norm);
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switch (norm) {
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case QPMS_NORMALISATION_KRISTENSSON:
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return 1.;
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break;
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case QPMS_NORMALISATION_TAYLOR:
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return l*(l+1);
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break;
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case QPMS_NORMALISATION_NONE:
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return l*(l+1) * 4 * M_PI / (2*l+1) * exp(lgamma(l+m+1)-lgamma(l-m+1));
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break;
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#ifdef USE_XU_ANTINORMALISATION // broken probably in legendre.c
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case QPMS_NORMALISATION_XU:
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{
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double fac = sqrt(4 * M_PI) / (2*l+1) * exp(lgamma(l+m+1)-lgamma(l-m+1));
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return fac * fac;
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}
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break;
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#endif
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default:
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assert(0);
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return NAN;
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}
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}
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#endif
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#endif //NORMALISATION_H
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