mirror of https://github.com/QMCPACK/qmcpack.git
136 lines
3.5 KiB
C++
136 lines
3.5 KiB
C++
//////////////////////////////////////////////////////////////////
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// (c) Copyright 2006- by Jeongnum Kim
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//////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////
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// National Center for Supercomputing Applications &
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// Materials Computation Center
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// University of Illinois, Urbana-Champaign
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// Urbana, IL 61801
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// e-mail: jnkim@ncsa.uiuc.edu
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// Tel: 217-244-6319 (NCSA) 217-333-3324 (MCC)
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//
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// Supported by
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// National Center for Supercomputing Applications, UIUC
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// Materials Computation Center, UIUC
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//////////////////////////////////////////////////////////////////
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// -*- C++ -*-
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/** @file LRJastrowSingleton.h
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* @brief Define a LRHandler with two template parameters
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*/
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#ifndef QMCPLUSPLUS_LRJASTROWSINGLETON_H
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#define QMCPLUSPLUS_LRJASTROWSINGLETON_H
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#include "LongRange/LRHandlerTemp.h"
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#include "Numerics/OneDimGridBase.h"
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#include "Numerics/OneDimGridFunctor.h"
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#include "Numerics/OneDimCubicSpline.h"
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#include <limits>
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namespace qmcplusplus
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{
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/** JastrowFunctor
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*
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* A Func for LRHandlerTemp. Four member functions have to be provided
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*
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* - reset(T volume) : reset the normalization factor
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* - operator() (T r, T rinv) : return a value of the original function e.g., 1.0/r
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* - Fk(T k, T rc)
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* - Xk(T k, T rc)
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*
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*/
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template<class T=double>
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struct JastrowFunctor
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{
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T Rs;
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T SqrtRs;
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T OneOverSqrtRs;
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T NormFactor;
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inline JastrowFunctor() {}
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void reset(ParticleSet& ref)
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{
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reset(ref.getTotalNum(),ref.Lattice.Volume);
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//NormFactor=4.0*M_PI/ref.Lattice.Volume;
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//T Density=ref.getTotalNum()/ref.Lattice.Volume;
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//Rs = std::pow(3.0/(4.0*M_PI*Density), 1.0/3.0);
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//SqrtRs=std::sqrt(Rs);
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//OneOverSqrtRs = 1.0 / SqrtRs;
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}
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void reset(ParticleSet& ref, T rs)
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{
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NormFactor=4.0*M_PI/ref.Lattice.Volume;
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Rs = rs;
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SqrtRs=std::sqrt(Rs);
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OneOverSqrtRs = 1.0 /SqrtRs;
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}
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/** reset by the number of particles and the volume
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* @param n number of particles
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* @param vol volume
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*/
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void reset(int n, T vol)
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{
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NormFactor=4.0*M_PI/vol;
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T Density=static_cast<T>(n)/vol;
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Rs = std::pow(3.0/(4.0*M_PI*Density), 1.0/3.0);
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SqrtRs=std::sqrt(Rs);
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OneOverSqrtRs = 1.0 / SqrtRs;
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}
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inline T operator()(T r, T rinv)
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{
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if(r< numeric_limits<T>::epsilon())
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return SqrtRs-0.5*r;
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else
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return Rs*rinv*(1.0-std::exp(-r*OneOverSqrtRs));
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//if (r > 1e-10) return Rs*rinv*(1.0 - std::exp(-r*OneOverSqrtRs));
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//return 1.0 / OneOverSqrtRs - 0.5 * r;
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}
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inline T df(T r, T rinv)
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{
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if(r< numeric_limits<T>::epsilon())
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return -0.5+r*OneOverSqrtRs/3.0;
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else
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{
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T exponential = std::exp(-r*OneOverSqrtRs);
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return -Rs*rinv*rinv*(1.0 - exponential) + exponential*rinv*SqrtRs;
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}
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}
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inline T Fk(T k, T rc)
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{
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return -Xk(k,rc);
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}
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inline T Xk(T k, T rc)
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{
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T coskr = std::cos(k*rc);
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T sinkr = std::sin(k*rc);
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T oneOverK = 1.0/k;
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return -NormFactor * Rs *
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(coskr*oneOverK*oneOverK
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- std::exp(-rc*OneOverSqrtRs)*(coskr - OneOverSqrtRs * sinkr * oneOverK)/(k*k+1.0/Rs));
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}
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};
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struct LRJastrowSingleton
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{
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typedef LRHandlerTemp<JastrowFunctor<double>,LPQHIBasis> LRHandlerType;
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static LRHandlerType* JastrowHandler;
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static LRHandlerType* getHandler(ParticleSet& ref, double kc);
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};
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}
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#endif
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/***************************************************************************
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* $RCSfile$ $Author$
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* $Revision$ $Date$
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* $Id$
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***************************************************************************/
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