nnp::EwaldTruncKolafaFixR Class Reference

#include <EwaldTruncKolafaFixR.h>

Inheritance diagram for nnp::EwaldTruncKolafaFixR:

Collaboration diagram for nnp::EwaldTruncKolafaFixR:

Public Member Functions
void	calculateParameters (EwaldGlobalSettings const &settings, EwaldStructureData const &sData, EwaldParameters &params) override
bool	publishedNewCutoffs () override
bool	isEstimateReliable (EwaldGlobalSettings const &settings, EwaldParameters const &params) const override
Public Member Functions inherited from nnp::IEwaldTrunc
virtual	~IEwaldTrunc ()=default

Private Member Functions
double	calculateEta (double const rCut, double const prec) const
double	calculateKCut (double const eta, double const prec) const
void	calculateC (double const qMax)

Private Attributes
double	volume = 0.0
double	fourPiEps = 1.0
std::size_t	numAtoms = 0
bool	newCutoffs = true
bool	newCutoffsWerePublished = false
double	C = 0.0

Detailed Description

Definition at line 13 of file EwaldTruncKolafaFixR.h.

Member Function Documentation

calculateParameters()

void nnp::EwaldTruncKolafaFixR::calculateParameters ( EwaldGlobalSettings const & settings, EwaldStructureData const & sData, EwaldParameters & params )

overridevirtual

Implements nnp::IEwaldTrunc.

Definition at line 12 of file EwaldTruncKolafaFixR.cpp.

    {
        size_t N = sData.getNumAtoms();
        double V = sData.getVolume();
 
        newCutoffs = (V != volume || N != numAtoms);
        if (!newCutoffs) return;
        newCutoffsWerePublished = false;
 
        volume = V;
        fourPiEps = settings.fourPiEps;
        numAtoms = N;
        double rCut = params.rCut;
        if (rCut == 0.0)
            throw std::runtime_error("ERROR: Real space cutoff of Ewald "
                                     "summation cannot be zero.");
 
        calculateC(settings.maxCharge);
        params.eta = calculateEta(rCut, settings.precision);
        params.kCut = calculateKCut(params.eta, settings.precision);
        return;
    }

References calculateC(), calculateEta(), calculateKCut(), nnp::EwaldParameters::eta, fourPiEps, nnp::EwaldStructureData::getNumAtoms(), nnp::EwaldStructureData::getVolume(), nnp::EwaldParameters::kCut, newCutoffs, newCutoffsWerePublished, numAtoms, nnp::EwaldParameters::rCut, and volume.

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publishedNewCutoffs()

bool nnp::EwaldTruncKolafaFixR::publishedNewCutoffs ( )

overridevirtual

Implements nnp::IEwaldTrunc.

Definition at line 36 of file EwaldTruncKolafaFixR.cpp.

    {
        bool answer = newCutoffsWerePublished;
        newCutoffsWerePublished = true;
        return answer;
    }

References newCutoffsWerePublished.

isEstimateReliable()

bool nnp::EwaldTruncKolafaFixR::isEstimateReliable ( EwaldGlobalSettings const & settings, EwaldParameters const & params ) const

overridevirtual

Implements nnp::IEwaldTrunc.

Definition at line 42 of file EwaldTruncKolafaFixR.cpp.

    {
        return params.eta >= settings.maxQSigma;
    }

References nnp::EwaldParameters::eta.

calculateEta()

double nnp::EwaldTruncKolafaFixR::calculateEta ( double const rCut, double const prec ) const

private

Definition at line 49 of file EwaldTruncKolafaFixR.cpp.

    {
        double x = sqrt(rCut/2) * prec / C;
        if (x >= 1.0)
            throw runtime_error("ERROR: Bad Ewald precision settings, try a "
                                "smaller value.");
        return rCut / sqrt(-2 * log(x));
    }

References C.

Referenced by calculateParameters().

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calculateKCut()

double nnp::EwaldTruncKolafaFixR::calculateKCut ( double const eta, double const prec ) const

private

Definition at line 59 of file EwaldTruncKolafaFixR.cpp.

    {
        double constexpr acceptError = 1.e-10;
        double relXError = 1.0;
        double relYError = 1.0;
        double y = eta * prec / (sqrt(2) * C);
 
        double kCut = 1.0/eta;
        double kCutOld;
        while (relXError > acceptError || relYError > acceptError)
        {
            kCutOld = kCut;
            kCut -= 2 * kCut / (1 + 2*pow(kCut * eta,2.0))
                    * (-1 + sqrt(kCut) * exp(pow(kCut * eta,2.0)/2) * y);
            // If kCut becomes negative, start with smaller value.
            if (kCut <= 0)
            {
                kCut = kCutOld / 2;
                continue;
            }
 
            relXError = abs((kCut - kCutOld) / kCut);
            relYError = abs((1/sqrt(kCut)
                        * exp(-pow(kCut * eta,2.0) / 2) - y) / y);
        }
        return kCut;
    }

References C.

Referenced by calculateParameters().

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calculateC()

void nnp::EwaldTruncKolafaFixR::calculateC ( double const qMax )

private

Definition at line 88 of file EwaldTruncKolafaFixR.cpp.

    {
        C = 2 * pow(qMax,2.0) * sqrt(numAtoms/volume) / fourPiEps;
    }

References C, fourPiEps, numAtoms, and volume.

Referenced by calculateParameters().

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Member Data Documentation

volume

double nnp::EwaldTruncKolafaFixR::volume = 0.0

private

Definition at line 25 of file EwaldTruncKolafaFixR.h.

Referenced by calculateC(), and calculateParameters().

fourPiEps

double nnp::EwaldTruncKolafaFixR::fourPiEps = 1.0

private

Definition at line 26 of file EwaldTruncKolafaFixR.h.

Referenced by calculateC(), and calculateParameters().

numAtoms

std::size_t nnp::EwaldTruncKolafaFixR::numAtoms = 0

private

Definition at line 27 of file EwaldTruncKolafaFixR.h.

Referenced by calculateC(), and calculateParameters().

newCutoffs

bool nnp::EwaldTruncKolafaFixR::newCutoffs = true

private

Definition at line 28 of file EwaldTruncKolafaFixR.h.

Referenced by calculateParameters().

newCutoffsWerePublished

bool nnp::EwaldTruncKolafaFixR::newCutoffsWerePublished = false

private

Definition at line 29 of file EwaldTruncKolafaFixR.h.

Referenced by calculateParameters(), and publishedNewCutoffs().

C

double nnp::EwaldTruncKolafaFixR::C = 0.0

private

Definition at line 31 of file EwaldTruncKolafaFixR.h.

Referenced by calculateC(), calculateEta(), and calculateKCut().

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The documentation for this class was generated from the following files:

• /home/runner/work/n2p2/n2p2/src/libnnp/EwaldTruncKolafaFixR.h
• /home/runner/work/n2p2/n2p2/src/libnnp/EwaldTruncKolafaFixR.cpp