SFNBranch Class Reference

Manages the state of QMC sections and handles population control for DMCs. More...

Inheritance diagram for SFNBranch:

Collaboration diagram for SFNBranch:

Classes
struct	VParams
	controlling parameters of full precision real type More...

Public Types
enum	{   B_DMC = 0, B_DMCSTAGE = 1, B_POPCONTROL = 2, B_USETAUEFF = 3,   B_CLEARHISTORY = 4, B_KILLNODES = 5, B_RESTART = 6, B_RMC = 7,   B_RMCSTAGE = 8, B_MODE_MAX = 10 }
enum	{   B_WARMUPSTEPS = 0, B_ENERGYUPDATEINTERVAL, B_COUNTER, B_TARGETWALKERS,   B_BRANCHINTERVAL, B_IPARAM_MAX }
enum	SimpleBranchVectorParameter {   TAU = 0, TAUEFF, ETRIAL, EREF,   ENOW, BRANCHMAX, BRANCHCUTOFF, BRANCHFILTER,   SIGMA2, SIGMA_BOUND, FEEDBACK, FILTERSCALE,   VPARAM_MAX = 17 }
	enum for vParam More...
using	MCPWalker = Walker< QMCTraits, PtclOnLatticeTraits >
using	BranchModeType = std::bitset< B_MODE_MAX >
using	IParamType = TinyVector< int, B_IPARAM_MAX >
	input parameters of integer types More...
using	SBVP = SimpleBranchVectorParameter
using	VParamType = VParams< SBVP >
Public Types inherited from QMCTraits
enum	{ DIM = OHMMS_DIM, DIM_VGL = OHMMS_DIM + 2 }
using	QTBase = QMCTypes< OHMMS_PRECISION, DIM >
using	QTFull = QMCTypes< OHMMS_PRECISION_FULL, DIM >
using	RealType = QTBase::RealType
using	ComplexType = QTBase::ComplexType
using	ValueType = QTBase::ValueType
using	PosType = QTBase::PosType
using	GradType = QTBase::GradType
using	TensorType = QTBase::TensorType
using	IndexType = OHMMS_INDEXTYPE
	define other types More...
using	FullPrecRealType = QTFull::RealType
using	FullPrecValueType = QTFull::ValueType
using	PropertySetType = RecordNamedProperty< FullPrecRealType >
	define PropertyList_t More...
using	PtclGrpIndexes = std::vector< std::pair< int, int > >

Public Member Functions
	SFNBranch (RealType tau, RealType feedback, DMCRefEnergyScheme)
	Constructor. More...
	SFNBranch (const SFNBranch &abranch)=delete
	copy constructor More...
	~SFNBranch ()
bool	phaseChanged (RealType psi0) const
void	advanceQMCCounter ()
	increment QMCCounter More...
void	regressQMCCounter ()
int	initParam (const MCPopulation &population, FullPrecRealType ene, FullPrecRealType var, bool fixW, bool killwalker)
	initialize branching parameters More...
RealType	branchWeightBare (RealType enew, RealType eold) const
	return the bare branch weight More...
RealType	branchWeight (FullPrecRealType enew, FullPrecRealType eold) const
	return the bare branch weight with a filtering using an energy window More...
RealType	symLinkAction (RealType logGf, RealType logGb, RealType enew, RealType eold) const
RealType	symLinkActionBare (RealType logGf, RealType logGb, RealType enew, RealType eold) const
RealType	DMCLinkAction (RealType enew, RealType eold) const
RealType	branchWeight (RealType enew, RealType eold, RealType scnew, RealType scold) const
	return the branch weight according to JCP1993 Umrigar et al. More...
RealType	branchWeight (RealType enew, RealType eold, RealType scnew, RealType scold, RealType p) const
	return the branch weight according to JCP1993 Umrigar et al. More...
RealType	getEref () const
RealType	getEtrial () const
RealType	getTau () const
RealType	getTauEff () const
int	getWarmupToDoSteps () const
void	updateParamAfterPopControl (const MCDataType< FullPrecRealType > &wc_ensemble_prop, int Nelec)
	perform branching More...
bool	put (xmlNodePtr cur)
	Parse the xml file for parameters. More...
void	registerParameters ()
	create map between the parameter name and variables More...
void	printStatus () const
	finalize the simulation More...

Private Member Functions
void	setBranchCutoff (FullPrecRealType variance, FullPrecRealType targetSigma, FullPrecRealType maxSigma, int Nelec=0)
	set branch cutoff, max, filter More...

Private Attributes
BranchModeType	BranchMode
IParamType	iParam
VParamType	vParam
int	WarmUpToDoSteps
	number of remaning steps in warmup, [0, iParam[B_WARMUPSTEPS]] More...
int	EtrialUpdateToDoSteps
	number of remaning steps in before adjusting ETRIAL, [0, iParam[B_ENERGYUPDATEINTERVAL]] More...
xmlNodePtr	myNode
	save xml element More...
DMCRefEnergy	ref_energy_collector
	collect energy and variance history More...
accumulator_set< RealType >	R2Accepted
	a simple accumulator for energy More...
accumulator_set< RealType >	R2Proposed
	a simple accumulator for energy More...
accumulator_set< RealType >	R2Center
	a simple accumulator for reptation's center slice More...
std::string	branching_cutoff_scheme
	scheme of branching cutoff More...
ParameterSet	m_param
	set of parameters More...
std::vector< std::string >	sParam
	string parameters More...

Friends
std::ostream &	operator<< (std::ostream &os, SFNBranch::VParamType &rhs)

Detailed Description

Manages the state of QMC sections and handles population control for DMCs.

Todo:

: Remove duplicate reading of Driver XML section with own copies of input parameters.

: Rename, it is the only branching class so its name is too much

: Use normal types for data members, don't be clever, the parameter enums violate KISS and make debugging annoying

: Remove as much state as possible.

QMCDriver object owns a SFNBranch to keep track of the progress of a qmc section. It implements several methods to control the population and trial energy during a DMC and evaluate the properties of a population, e.g., energy, variance, population etc.

See also

{http://qmcpack.cmscc.org/qmc-basics}

Steps in SFNB states machine

1. Construction (gets global walker number (rank or section wide?)
2. put(reads driver XML node yet again)
3. InitParam a. If TargetWalkers isn't known aa. allreduce and updates MCMW globalWalkers. bb. sets target walkers to whatever current total active walkers is. b. If not a restart aa. saves fixW and killWalker to internal params, otherwise just discards. bb. updates SFNB copy of MAX/MINWALKRS from walker controller, these were set in constructer but I guess thats ony if this is a restart
4. updateParam after each walker control branch (outside SFNBranch) a. Not first iter during warmup then call WalkerController branch. else call WC doNotBranch, returns pop_now b. copy a bunch a state from WC to SFNB (should be with respect to pop_now - number of released nodes) c. If using taueff update that based on acceptance ration and current tau. d. If not warmup calculate ETRIAL based on EREF and feedback * log(TargetWalkers) - log(pop_now) e. set WC's TrialEnergy

Definition at line 63 of file SFNBranch.h.

Member Typedef Documentation

BranchModeType

using BranchModeType = std::bitset<B_MODE_MAX>

Definition at line 94 of file SFNBranch.h.

IParamType

using IParamType = TinyVector<int, B_IPARAM_MAX>

input parameters of integer types

Since

2008-05-05

Definition at line 113 of file SFNBranch.h.

MCPWalker

using MCPWalker = Walker<QMCTraits, PtclOnLatticeTraits>

Definition at line 66 of file SFNBranch.h.

SBVP

using SBVP = SimpleBranchVectorParameter

Definition at line 138 of file SFNBranch.h.

VParamType

using VParamType = VParams<SBVP>

Definition at line 151 of file SFNBranch.h.

Member Enumeration Documentation

anonymous enum

anonymous enum

enum for booleans

Since

2008-05-05

Enumerator
B_DMC	1 for dmc, 0 for anything else
B_DMCSTAGE	1 for main, 0 for wamrup
B_POPCONTROL	1 for the standard dmc, 0 for the comb method
B_USETAUEFF	1 to use taueff accordning to JCP 93, 0 to use tau
B_CLEARHISTORY	1 to clear the history
B_KILLNODES	1 to kill walkers when a node crossing is detected
B_RESTART	1 if restarting
B_RMC	1 for rmc, 0 for anything else
B_RMCSTAGE	1 for main, 0 for warmup
B_MODE_MAX	size of BranchMode

Definition at line 71 of file SFNBranch.h.

  {
    B_DMC = 0 /**< 1 for dmc, 0 for anything else */
    ,
    B_DMCSTAGE = 1 /**< 1 for main, 0 for wamrup  */
    ,
    B_POPCONTROL = 2 /**< 1 for the standard dmc, 0 for the comb method */
    ,
    B_USETAUEFF = 3 /**< 1 to use taueff accordning to JCP 93, 0 to use tau */
    ,
    B_CLEARHISTORY = 4 /**< 1 to clear the history */
    ,
    B_KILLNODES = 5 /**< 1 to kill walkers when a node crossing is detected */
    ,
    B_RESTART = 6 /**< 1 if restarting */
    ,
    B_RMC = 7 /**< 1 for rmc, 0 for anything else */
    ,
    B_RMCSTAGE = 8 /**< 1 for main, 0 for warmup */
    ,
    B_MODE_MAX = 10 /**< size of BranchMode */
  };

anonymous enum

anonymous enum

enum for iParam std::bitset<B_IPARAM_MAX> When introducing a new iParam, check if B_IPARAM_MAX is sufficiently large. Use multiples of 8 Why? Much easier to use bool flags. Are these ever serialized?

Enumerator
B_WARMUPSTEPS	warmup steps, valid when BranchMode[D_DMCSTAGE] == 0
B_ENERGYUPDATEINTERVAL	frequency of the trial energy updates, default 1
B_COUNTER	counter for tracking object state
B_TARGETWALKERS	target total number of walkers per mpi group
B_BRANCHINTERVAL	interval between branch, see population control
B_IPARAM_MAX	size of iParam

Definition at line 100 of file SFNBranch.h.

  {
    B_WARMUPSTEPS = 0,      /**< warmup steps, valid when BranchMode[D_DMCSTAGE] == 0 */
    B_ENERGYUPDATEINTERVAL, /**< frequency of the trial energy updates, default 1 */
    B_COUNTER,              /**< counter for tracking object state */
    B_TARGETWALKERS,        /**< target total number of walkers per mpi group */
    B_BRANCHINTERVAL,       /**< interval between branch, see population control */
    B_IPARAM_MAX            /**< size of iParam */
  };

SimpleBranchVectorParameter

enum SimpleBranchVectorParameter

strong

enum for vParam

Easy serialization is a relatively minor concern compared to the annoyance this causes elsewhere.

Enumerator
TAU
TAUEFF
ETRIAL
EREF
ENOW
BRANCHMAX
BRANCHCUTOFF
BRANCHFILTER
SIGMA2
SIGMA_BOUND
FEEDBACK
FILTERSCALE
VPARAM_MAX

Definition at line 120 of file SFNBranch.h.

  {
    TAU = 0,
    TAUEFF, // effective time step
    ETRIAL, // Trial energy
    EREF,   // Estimate of the ground state energy based on the single step population average during warmup
            // or the historical average of population average post warmup.
            // Center of the branching cutoff energy window.
    ENOW,   // weighted average energy of the population in the current step
    BRANCHMAX,
    BRANCHCUTOFF,
    BRANCHFILTER,
    SIGMA2,
    SIGMA_BOUND,
    FEEDBACK,
    FILTERSCALE,
    VPARAM_MAX = 17 // four extra, why? Sloppy or undocumented hack?
  };

Constructor & Destructor Documentation

SFNBranch() [1/2]

SFNBranch	(	RealType	tau,
		RealType	feedback,
		DMCRefEnergyScheme	refenergy_update_scheme
	)

Constructor.

Definition at line 34 of file SFNBranch.cpp.

References SFNBranch::B_BRANCHINTERVAL, SFNBranch::B_CLEARHISTORY, SFNBranch::B_COUNTER, SFNBranch::B_DMCSTAGE, SFNBranch::B_ENERGYUPDATEINTERVAL, SFNBranch::B_KILLNODES, SFNBranch::B_POPCONTROL, SFNBranch::B_TARGETWALKERS, SFNBranch::B_USETAUEFF, SFNBranch::B_WARMUPSTEPS, SFNBranch::branching_cutoff_scheme, SFNBranch::BranchMode, qmcplusplus::DUMMYOPT, qmcplusplus::Units::charge::e, SFNBranch::FEEDBACK, SFNBranch::FILTERSCALE, SFNBranch::iParam, SFNBranch::R2Accepted, SFNBranch::R2Proposed, SFNBranch::registerParameters(), SFNBranch::SIGMA_BOUND, SFNBranch::sParam, SFNBranch::TAU, SFNBranch::TAUEFF, and SFNBranch::vParam.

    : WarmUpToDoSteps(0),
      EtrialUpdateToDoSteps(0),
      myNode(NULL),
      ref_energy_collector(refenergy_update_scheme, std::max(1, static_cast<int>(1.0 / (feedback * tau))))
{
  BranchMode.set(B_DMCSTAGE, 0);     //warmup stage
  BranchMode.set(B_POPCONTROL, 1);   //use standard DMC
  BranchMode.set(B_USETAUEFF, 1);    //use taueff
  BranchMode.set(B_CLEARHISTORY, 0); //clear history and start with the current average
  BranchMode.set(B_KILLNODES, 0);    //when killing walkers at nodes etrial is updated differently
  vParam.fill(1.0);
  vParam[SBVP::TAU]         = tau;
  vParam[SBVP::TAUEFF]      = tau;
  vParam[SBVP::FEEDBACK]    = feedback;
  vParam[SBVP::FILTERSCALE] = 10;
  vParam[SBVP::SIGMA_BOUND] = 10;
  R2Accepted(1.0e-10);
  R2Proposed(1.0e-10);
  //set the default values for integer parameters
  iParam[B_WARMUPSTEPS]          = 200;
  iParam[B_ENERGYUPDATEINTERVAL] = 1;
  iParam[B_BRANCHINTERVAL]       = 1;
  iParam[B_TARGETWALKERS]        = 0;
  iParam[B_COUNTER]              = -1;
  //default is no
  sParam.resize(DUMMYOPT, "no");
  //default is classic
  branching_cutoff_scheme = "classic";
  registerParameters();
}

SFNBranch() [2/2]

SFNBranch ( const SFNBranch &  abranch )

delete

copy constructor

~SFNBranch()

~SFNBranch ( )

default

Member Function Documentation

advanceQMCCounter()

void advanceQMCCounter ( )

inline

increment QMCCounter

QMCCounter is the number of times any QMC section is processed.

Definition at line 175 of file SFNBranch.h.

References SFNBranch::B_COUNTER, and SFNBranch::iParam.

{ iParam[B_COUNTER]++; }

branchWeight() [1/3]

RealType branchWeight ( FullPrecRealType  enew, FullPrecRealType  eold  ) const

inline

return the bare branch weight with a filtering using an energy window

Cutoff values are set by the variance

Definition at line 199 of file SFNBranch.h.

References SFNBranch::BRANCHCUTOFF, SFNBranch::BRANCHFILTER, SFNBranch::BRANCHMAX, SFNBranch::EREF, SFNBranch::ETRIAL, qmcplusplus::exp(), SFNBranch::TAUEFF, and SFNBranch::vParam.

Referenced by DMCBatched::advanceWalkers().

  {
    FullPrecRealType taueff_ = vParam[SBVP::TAUEFF] * 0.5;
    FullPrecRealType x       = std::max(vParam[SBVP::EREF] - enew, vParam[SBVP::EREF] - eold);
    if (x > vParam[SBVP::BRANCHMAX])
      taueff_ = 0.0;
    else if (x > vParam[SBVP::BRANCHCUTOFF])
      taueff_ *= (1.0 - (x - vParam[SBVP::BRANCHCUTOFF]) * vParam[SBVP::BRANCHFILTER]);
    return std::exp(taueff_ * (vParam[SBVP::ETRIAL] * 2.0 - enew - eold));
  }

branchWeight() [2/3]

RealType branchWeight ( RealType  enew, RealType  eold, RealType  scnew, RealType  scold  ) const

inline

return the branch weight according to JCP1993 Umrigar et al.

Appendix A p=1, q=0

Parameters

enew	new energy
eold	old energy
scnew
scold

Definition at line 249 of file SFNBranch.h.

References SFNBranch::EREF, SFNBranch::ETRIAL, qmcplusplus::exp(), SFNBranch::TAUEFF, and SFNBranch::vParam.

  {
    FullPrecRealType s1 = (vParam[SBVP::ETRIAL] - vParam[SBVP::EREF]) + (vParam[SBVP::EREF] - enew) * scnew;
    FullPrecRealType s0 = (vParam[SBVP::ETRIAL] - vParam[SBVP::EREF]) + (vParam[SBVP::EREF] - eold) * scold;
    return std::exp(vParam[SBVP::TAUEFF] * 0.5 * (s1 + s0));
  }

branchWeight() [3/3]

RealType branchWeight ( RealType  enew, RealType  eold, RealType  scnew, RealType  scold, RealType  p  ) const

inline

return the branch weight according to JCP1993 Umrigar et al.

Appendix A

Parameters

enew	new energy
eold	old energy
scnew
scold
p	acceptance ratio

Definition at line 263 of file SFNBranch.h.

References SFNBranch::EREF, SFNBranch::ETRIAL, qmcplusplus::exp(), SFNBranch::TAUEFF, and SFNBranch::vParam.

  {
    FullPrecRealType s1 = (vParam[SBVP::ETRIAL] - vParam[SBVP::EREF]) + (vParam[SBVP::EREF] - enew) * scnew;
    FullPrecRealType s0 = (vParam[SBVP::ETRIAL] - vParam[SBVP::EREF]) + (vParam[SBVP::EREF] - eold) * scold;
    return std::exp(vParam[SBVP::TAUEFF] * (p * 0.5 * (s1 - s0) + s0));
    //return std::exp(TauEff*(p*0.5*(sp-sq)+sq));
  }

branchWeightBare()

RealType branchWeightBare ( RealType  enew, RealType  eold  ) const

inline

return the bare branch weight

This is equivalent to calling branchWeight(enew,eold,1.0,1.0)

Definition at line 190 of file SFNBranch.h.

References SFNBranch::ETRIAL, qmcplusplus::exp(), SFNBranch::TAUEFF, and SFNBranch::vParam.

  {
    return std::exp(vParam[SBVP::TAUEFF] * (vParam[SBVP::ETRIAL] - 0.5 * (enew + eold)));
  }

DMCLinkAction()

RealType DMCLinkAction ( RealType  enew, RealType  eold  ) const

inline

Definition at line 233 of file SFNBranch.h.

References SFNBranch::BRANCHCUTOFF, SFNBranch::BRANCHFILTER, SFNBranch::BRANCHMAX, SFNBranch::EREF, SFNBranch::TAUEFF, and SFNBranch::vParam.

  {
    RealType taueff_ = vParam[SBVP::TAUEFF] * 0.5;
    RealType x       = std::max(vParam[SBVP::EREF] - enew, vParam[SBVP::EREF] - eold);
    if (x > vParam[SBVP::BRANCHMAX])
      taueff_ = 0.0;
    else if (x > vParam[SBVP::BRANCHCUTOFF])
      taueff_ *= (1.0 - (x - vParam[SBVP::BRANCHCUTOFF]) * vParam[SBVP::BRANCHFILTER]);
    return taueff_ * (enew + eold);
  }

getEref()

RealType getEref ( ) const

inline

Definition at line 271 of file SFNBranch.h.

References SFNBranch::EREF, and SFNBranch::vParam.

{ return vParam[SBVP::EREF]; }

getEtrial()

RealType getEtrial ( ) const

inline

Definition at line 272 of file SFNBranch.h.

References SFNBranch::ETRIAL, and SFNBranch::vParam.

{ return vParam[SBVP::ETRIAL]; }

getTau()

RealType getTau ( ) const

inline

Definition at line 273 of file SFNBranch.h.

References SFNBranch::TAU, and SFNBranch::vParam.

{ return vParam[SBVP::TAU]; }

getTauEff()

RealType getTauEff ( ) const

inline

Definition at line 274 of file SFNBranch.h.

References SFNBranch::TAUEFF, and SFNBranch::vParam.

{ return vParam[SBVP::TAUEFF]; }

getWarmupToDoSteps()

int getWarmupToDoSteps ( ) const

inline

Definition at line 276 of file SFNBranch.h.

References SFNBranch::WarmUpToDoSteps.

{ return WarmUpToDoSteps; }

initParam()

int initParam	(	const MCPopulation &	population,
		FullPrecRealType	ene,
		FullPrecRealType	var,
		bool	fixW,
		bool	killwalker
	)

initialize branching parameters

Parameters

pop	Population of Walkers
fixW	true, if reconfiguration with the fixed number of walkers is used
killwalker

Returns

number of copies to make in case targetwalkers changed

FIXME, magic number 50

Definition at line 94 of file SFNBranch.cpp.

References qmcplusplus::app_log(), SFNBranch::B_COUNTER, SFNBranch::B_DMC, SFNBranch::B_DMCSTAGE, SFNBranch::B_KILLNODES, SFNBranch::B_POPCONTROL, SFNBranch::B_TARGETWALKERS, SFNBranch::B_WARMUPSTEPS, SFNBranch::BRANCHCUTOFF, SFNBranch::branching_cutoff_scheme, SFNBranch::BRANCHMAX, SFNBranch::BranchMode, SFNBranch::EREF, SFNBranch::ETRIAL, SFNBranch::FEEDBACK, MCPopulation::get_golden_electrons(), MCPopulation::get_num_global_walkers(), ParticleSet::getTotalNum(), SFNBranch::iParam, SFNBranch::R2Accepted, SFNBranch::R2Proposed, accumulator_set< T, typename >::result(), SFNBranch::setBranchCutoff(), SFNBranch::SIGMA2, SFNBranch::SIGMA_BOUND, SFNBranch::TAU, SFNBranch::TAUEFF, and SFNBranch::vParam.

{
  app_log() << "  START ALL OVER " << std::endl;
  BranchMode.set(B_POPCONTROL, !fixW); //fixW -> 0
  BranchMode.set(B_KILLNODES, killwalker);

  BranchMode.set(B_DMC, 1);                               //set DMC
  BranchMode.set(B_DMCSTAGE, iParam[B_WARMUPSTEPS] == 0); //use warmup
  vParam[SBVP::ETRIAL] = ene;
  vParam[SBVP::EREF]   = ene;
  vParam[SBVP::SIGMA2] = var;
  vParam[SBVP::TAUEFF] = vParam[SBVP::TAU] * R2Accepted.result() / R2Proposed.result();
  /// FIXME, magic number 50
  setBranchCutoff(vParam[SBVP::SIGMA2], vParam[SBVP::SIGMA_BOUND], 50, population.get_golden_electrons().getTotalNum());

  int nwtot_now = population.get_num_global_walkers();
  if (iParam[B_TARGETWALKERS] == 0)
    iParam[B_TARGETWALKERS] = nwtot_now;

  app_log() << "  QMC counter             = " << iParam[B_COUNTER] << std::endl;
  app_log() << "  time step               = " << vParam[SBVP::TAU] << std::endl;
  app_log() << "  effective time step     = " << vParam[SBVP::TAUEFF] << std::endl;
  app_log() << "  trial energy            = " << vParam[SBVP::ETRIAL] << std::endl;
  app_log() << "  reference energy        = " << vParam[SBVP::EREF] << std::endl;
  app_log() << "  reference variance      = " << vParam[SBVP::SIGMA2] << std::endl;
  app_log() << "  Feedback                = " << vParam[SBVP::FEEDBACK] << std::endl;
  app_log() << "  target walkers          = " << iParam[B_TARGETWALKERS] << std::endl;
  app_log() << "  branching cutoff scheme = " << branching_cutoff_scheme << std::endl;
  app_log() << "  branch cutoff, max      = " << vParam[SBVP::BRANCHCUTOFF] << " " << vParam[SBVP::BRANCHMAX]
            << std::endl;
  app_log() << "  QMC Status (BranchMode) = " << BranchMode << std::endl;

  return int(round(double(iParam[B_TARGETWALKERS]) / double(nwtot_now)));
}

phaseChanged()

bool phaseChanged ( RealType  psi0 ) const

inline

Definition at line 161 of file SFNBranch.h.

References qmcplusplus::cos().

Referenced by DMCBatched::advanceWalkers().

  {
// TODO: remove ifdef
#if defined(QMC_COMPLEX)
    return false;
#else
    return std::cos(psi0) < std::numeric_limits<RealType>::epsilon();
#endif
  }

printStatus()

void printStatus

(

)

const

finalize the simulation

Definition at line 231 of file SFNBranch.cpp.

References qmcplusplus::app_log(), SFNBranch::B_COUNTER, SFNBranch::B_RMC, SFNBranch::B_TARGETWALKERS, SFNBranch::BRANCHCUTOFF, SFNBranch::BRANCHMAX, SFNBranch::BranchMode, SFNBranch::EREF, SFNBranch::ETRIAL, SFNBranch::FEEDBACK, SFNBranch::iParam, SFNBranch::SIGMA2, SFNBranch::TAU, SFNBranch::TAUEFF, and SFNBranch::vParam.

{
  std::ostringstream o;
  //running RMC
  if (BranchMode[B_RMC])
  {
    o << "====================================================";
    o << "\n  End of a RMC section";
    o << "\n    QMC counter                   = " << iParam[B_COUNTER];
    o << "\n    time step                     = " << vParam[SBVP::TAU];
    o << "\n    effective time step           = " << vParam[SBVP::TAUEFF];
    o << "\n    reference energy              = " << vParam[SBVP::EREF];
    o << "\n    reference variance            = " << vParam[SBVP::SIGMA2];
    o << "\n    cutoff energy                 = " << vParam[SBVP::BRANCHCUTOFF] << " " << vParam[SBVP::BRANCHMAX];
    o << "\n    QMC Status (BranchMode)       = " << BranchMode;
    o << "\n====================================================";
  }
  else // running DMC
  {
    o << "====================================================";
    o << "\n  End of a DMC section";
    o << "\n    QMC counter                   = " << iParam[B_COUNTER];
    o << "\n    time step                     = " << vParam[SBVP::TAU];
    o << "\n    effective time step           = " << vParam[SBVP::TAUEFF];
    o << "\n    trial energy                  = " << vParam[SBVP::ETRIAL];
    o << "\n    reference energy              = " << vParam[SBVP::EREF];
    o << "\n    reference variance            = " << vParam[SBVP::SIGMA2];
    o << "\n    target walkers                = " << iParam[B_TARGETWALKERS];
    o << "\n    branch cutoff                 = " << vParam[SBVP::BRANCHCUTOFF] << " " << vParam[SBVP::BRANCHMAX];
    o << "\n    Feedback                      = " << vParam[SBVP::FEEDBACK];
    o << "\n    QMC Status (BranchMode)       = " << BranchMode;
    o << "\n====================================================";
  }
  app_log() << o.str() << std::endl;
}

put()

bool put

(

xmlNodePtr

cur

)

Parse the xml file for parameters.

Parameters

cur	current xmlNode

Few important parameters are:

• en_ref: a reference energy
• num_gen: number of generations to reach equilibrium, used in the feedback parameter

Definition at line 277 of file SFNBranch.cpp.

References SFNBranch::B_ENERGYUPDATEINTERVAL, SFNBranch::B_WARMUPSTEPS, SFNBranch::EtrialUpdateToDoSteps, SFNBranch::iParam, SFNBranch::m_param, SFNBranch::myNode, ParameterSet::put(), and SFNBranch::WarmUpToDoSteps.

{
  //save it
  myNode = cur;
  m_param.put(cur);
  WarmUpToDoSteps       = iParam[B_WARMUPSTEPS];
  EtrialUpdateToDoSteps = iParam[B_ENERGYUPDATEINTERVAL];
  return true;
}

registerParameters()

void registerParameters

(

)

create map between the parameter name and variables

Definition at line 68 of file SFNBranch.cpp.

References ParameterSet::add(), SFNBranch::B_BRANCHINTERVAL, SFNBranch::B_ENERGYUPDATEINTERVAL, SFNBranch::B_TARGETWALKERS, SFNBranch::B_WARMUPSTEPS, SFNBranch::branching_cutoff_scheme, SFNBranch::EREF, SFNBranch::FILTERSCALE, SFNBranch::iParam, SFNBranch::m_param, qmcplusplus::MIXDMCOPT, SFNBranch::SIGMA_BOUND, SFNBranch::sParam, SFNBranch::TAU, qmcplusplus::USETAUOPT, and SFNBranch::vParam.

Referenced by SFNBranch::SFNBranch().

{
  m_param.add(iParam[B_WARMUPSTEPS], "warmupSteps");
  m_param.add(iParam[B_WARMUPSTEPS], "warmupsteps");
  m_param.add(iParam[B_ENERGYUPDATEINTERVAL], "energyUpdateInterval");
  m_param.add(iParam[B_BRANCHINTERVAL], "branchInterval");
  m_param.add(iParam[B_TARGETWALKERS], "targetWalkers");
  m_param.add(iParam[B_TARGETWALKERS], "targetwalkers");
  m_param.add(iParam[B_TARGETWALKERS], "target_walkers");
  //trial energy
  m_param.add(vParam[SBVP::EREF], "refEnergy");
  m_param.add(vParam[SBVP::EREF], "ref_energy");
  m_param.add(vParam[SBVP::EREF], "en_ref");
  m_param.add(vParam[SBVP::TAU], "tau");
  m_param.add(vParam[SBVP::TAU], "timestep");
  m_param.add(vParam[SBVP::TAU], "timeStep");
  m_param.add(vParam[SBVP::TAU], "TimeStep");
  //filterscale:  sets the filtercutoff to sigma*filterscale
  m_param.add(vParam[SBVP::FILTERSCALE], "filterscale");
  m_param.add(vParam[SBVP::SIGMA_BOUND], "sigmaBound");
  //turn on/off effective tau onl for time-step error comparisons
  m_param.add(sParam[USETAUOPT], "useBareTau");
  m_param.add(sParam[MIXDMCOPT], "warmupByReconfiguration");
  m_param.add(branching_cutoff_scheme, "branching_cutoff_scheme");
}

regressQMCCounter()

void regressQMCCounter ( )

inline

Definition at line 176 of file SFNBranch.h.

References SFNBranch::B_COUNTER, and SFNBranch::iParam.

{ iParam[B_COUNTER]--; }

setBranchCutoff()

void setBranchCutoff ( FullPrecRealType  variance, FullPrecRealType  targetSigma, FullPrecRealType  maxSigma, int  Nelec = 0  )

private

set branch cutoff, max, filter

Definition at line 287 of file SFNBranch.cpp.

References APP_ABORT, SFNBranch::BRANCHCUTOFF, SFNBranch::BRANCHFILTER, SFNBranch::branching_cutoff_scheme, SFNBranch::BRANCHMAX, omptarget::min(), qmcplusplus::sqrt(), SFNBranch::TAU, and SFNBranch::vParam.

Referenced by SFNBranch::initParam(), and SFNBranch::updateParamAfterPopControl().

{
  if (branching_cutoff_scheme == "DRV")
  {
    // eq.(3), J. Chem. Phys. 89, 3629 (1988).
    // eq.(9), J. Chem. Phys. 99, 2865 (1993).
    vParam[SBVP::BRANCHCUTOFF] = 2.0 / std::sqrt(vParam[SBVP::TAU]);
  }
  else if (branching_cutoff_scheme == "ZSGMA")
  {
    // eq.(6), Phys. Rev. B 93, 241118(R) (2016)
    // do nothing if Nelec is not passed in.
    if (Nelec > 0)
      vParam[SBVP::BRANCHCUTOFF] = 0.2 * std::sqrt(Nelec / vParam[SBVP::TAU]);
  }
  else if (branching_cutoff_scheme == "YL")
  {
    // a scheme from Ye Luo.
    vParam[SBVP::BRANCHCUTOFF] = std::sqrt(variance) * std::min(targetSigma, std::sqrt(1.0 / vParam[SBVP::TAU]));
  }
  else if (branching_cutoff_scheme == "classic")
  {
    // default QMCPACK choice which is the same as v3.0.0 and before.
    vParam[SBVP::BRANCHCUTOFF] = std::min(std::max(variance * targetSigma, maxSigma), 2.5 / vParam[SBVP::TAU]);
  }
  else
    APP_ABORT("SFNBranch::setBranchCutoff unknown branching cutoff scheme " + branching_cutoff_scheme);

  vParam[SBVP::BRANCHMAX]    = vParam[SBVP::BRANCHCUTOFF] * 1.5;
  vParam[SBVP::BRANCHFILTER] = 1.0 / (vParam[SBVP::BRANCHMAX] - vParam[SBVP::BRANCHCUTOFF]);
}

symLinkAction()

RealType symLinkAction ( RealType  logGf, RealType  logGb, RealType  enew, RealType  eold  ) const

inline

Definition at line 210 of file SFNBranch.h.

References SFNBranch::BRANCHCUTOFF, SFNBranch::BRANCHFILTER, SFNBranch::BRANCHMAX, SFNBranch::EREF, SFNBranch::TAUEFF, and SFNBranch::vParam.

  {
    RealType driftaction = -0.5 * (logGf + logGb);
    //RealType energyaction =
    RealType taueff_ = vParam[SBVP::TAUEFF] * 0.5;
    RealType x       = std::max(vParam[SBVP::EREF] - enew, vParam[SBVP::EREF] - eold);
    if (x > vParam[SBVP::BRANCHMAX])
      taueff_ = 0.0;
    else if (x > vParam[SBVP::BRANCHCUTOFF])
      taueff_ *= (1.0 - (x - vParam[SBVP::BRANCHCUTOFF]) * vParam[SBVP::BRANCHFILTER]);
    RealType energyaction = taueff_ * (enew + eold);
    return driftaction + energyaction;
  }

symLinkActionBare()

RealType symLinkActionBare ( RealType  logGf, RealType  logGb, RealType  enew, RealType  eold  ) const

inline

Definition at line 224 of file SFNBranch.h.

References SFNBranch::TAUEFF, and SFNBranch::vParam.

  {
    RealType driftaction  = -0.5 * (logGf + logGb);
    RealType taueff_      = vParam[SBVP::TAUEFF] * 0.5;
    RealType energyaction = taueff_ * (enew + eold);
    // RealType wavefunctionaction= -psinew + psiold;
    return driftaction + energyaction;
  }

updateParamAfterPopControl()

void updateParamAfterPopControl	(	const MCDataType< FullPrecRealType > &	wc_ensemble_prop,
		int	Nelec
	)

perform branching

Parameters

iter	current step
w	Walker configuration

FIXME vParam[SBVP::ETRIAL] = vParam[SBVP::EREF];

FIXME vParam[SBVP::ETRIAL] = vParam[SBVP::ENOW];

Definition at line 133 of file SFNBranch.cpp.

References qmcplusplus::app_log(), SFNBranch::B_DMCSTAGE, SFNBranch::B_ENERGYUPDATEINTERVAL, SFNBranch::B_KILLNODES, SFNBranch::B_POPCONTROL, SFNBranch::B_TARGETWALKERS, SFNBranch::B_USETAUEFF, SFNBranch::B_WARMUPSTEPS, SFNBranch::BRANCHCUTOFF, SFNBranch::BRANCHMAX, SFNBranch::BranchMode, DMCRefEnergy::count(), MCDataType< T >::Energy, SFNBranch::ENOW, SFNBranch::EREF, SFNBranch::ETRIAL, SFNBranch::EtrialUpdateToDoSteps, SFNBranch::FEEDBACK, DMCRefEnergy::getEnergyVariance(), SFNBranch::iParam, MCDataType< T >::LivingFraction, qmcplusplus::log(), qmcplusplus::MIXDMCOPT, DMCRefEnergy::pushWeightEnergyVariance(), MCDataType< T >::R2Accepted, SFNBranch::R2Accepted, MCDataType< T >::R2Proposed, SFNBranch::R2Proposed, SFNBranch::ref_energy_collector, accumulator_set< T, typename >::result(), SFNBranch::setBranchCutoff(), SFNBranch::SIGMA2, SFNBranch::SIGMA_BOUND, SFNBranch::sParam, SFNBranch::TAU, SFNBranch::TAUEFF, MCDataType< T >::Variance, SFNBranch::vParam, SFNBranch::WarmUpToDoSteps, and MCDataType< T >::Weight.

{
  //target weight
  const auto logN = std::log(static_cast<FullPrecRealType>(iParam[B_TARGETWALKERS]));
  //population weight before branching
  const FullPrecRealType pop_weight = wc_ensemble_prop.Weight;
  //current energy
  vParam[SBVP::ENOW] = wc_ensemble_prop.Energy;

  R2Accepted(wc_ensemble_prop.R2Accepted);
  R2Proposed(wc_ensemble_prop.R2Proposed);
  if (BranchMode[B_USETAUEFF])
    vParam[SBVP::TAUEFF] = vParam[SBVP::TAU] * R2Accepted.result() / R2Proposed.result();

  if (BranchMode[B_DMCSTAGE]) // main stage after warmup
  {
    if (WarmUpToDoSteps != 0)
      throw UniformCommunicateError("Bug: WarmUpToDoSteps should be 0 after warmup.");

    // assuming ENOW only fluctuates around the mean (EREF) once warmup completes.
    const auto ene = BranchMode[B_KILLNODES]
        ? vParam[SBVP::ENOW] - std::log(wc_ensemble_prop.LivingFraction) / vParam[SBVP::TAUEFF]
        : vParam[SBVP::ENOW];
    ref_energy_collector.pushWeightEnergyVariance(wc_ensemble_prop.Weight, ene, wc_ensemble_prop.Variance);
    // update the reference energy
    auto [ene_avg, var_avg] = ref_energy_collector.getEnergyVariance();
    vParam[SBVP::EREF]      = ene_avg;

    // update Etrial based on EREF
    if (BranchMode[B_POPCONTROL])
    {
      --EtrialUpdateToDoSteps;
      if (EtrialUpdateToDoSteps == 0)
      {
        vParam[SBVP::ETRIAL]  = vParam[SBVP::EREF] + vParam[SBVP::FEEDBACK] * (logN - std::log(pop_weight));
        EtrialUpdateToDoSteps = iParam[B_ENERGYUPDATEINTERVAL];
      }
    }
    else
    {
      throw UniformCommunicateError("Bug: FIXME SBVP::EREF should be calculated based on weights");
      /// FIXME vParam[SBVP::ETRIAL] = vParam[SBVP::EREF];
    }
  }
  else //warmup
  {
    if (WarmUpToDoSteps == 0)
      throw UniformCommunicateError("Bug: WarmUpToDoSteps should be larger than 0 during warmup.");

    // Use Enow as the best estimate of ground state energy during warmup.
    vParam[SBVP::EREF] = vParam[SBVP::ENOW];
    // update Etrial based on Enow as Enow is not yet converged in warmup stage
    if (BranchMode[B_POPCONTROL])
    {
      if (BranchMode[B_KILLNODES])
        vParam[SBVP::ETRIAL] = (0.00 * vParam[SBVP::EREF] + 1.0 * vParam[SBVP::ENOW]) +
            vParam[SBVP::FEEDBACK] * (logN - std::log(pop_weight)) -
            std::log(wc_ensemble_prop.LivingFraction) / vParam[SBVP::TAU];
      else
        vParam[SBVP::ETRIAL] = vParam[SBVP::ENOW] + (logN - std::log(pop_weight)) / vParam[SBVP::TAU];
    }
    else
    {
      throw UniformCommunicateError("Bug: FIXME SBVP::EREF should be calculated based on weights");
      /// FIXME vParam[SBVP::ETRIAL] = vParam[SBVP::ENOW];
    }

    --WarmUpToDoSteps;
    if (WarmUpToDoSteps == 0) //warmup is done
    {
      if (ref_energy_collector.count())
        throw UniformCommunicateError("Bug: ref_energy_collector should not have been used during warmup.");

      vParam[SBVP::SIGMA2] = wc_ensemble_prop.Variance;
      setBranchCutoff(vParam[SBVP::SIGMA2], vParam[SBVP::SIGMA_BOUND], 10, Nelec);
      app_log() << "\n Warmup is completed after " << iParam[B_WARMUPSTEPS] << std::endl;
      if (BranchMode[B_USETAUEFF])
        app_log() << "\n  TauEff     = " << vParam[SBVP::TAUEFF]
                  << "\n TauEff/Tau = " << vParam[SBVP::TAUEFF] / vParam[SBVP::TAU];
      else
        app_log() << "\n  TauEff proposed   = " << vParam[SBVP::TAUEFF] * R2Accepted.result() / R2Proposed.result();
      app_log() << "\n  Etrial     = " << vParam[SBVP::ETRIAL] << std::endl;
      app_log() << " Population average of energy = " << vParam[SBVP::ENOW] << std::endl;
      app_log() << "                  Variance = " << vParam[SBVP::SIGMA2] << std::endl;
      app_log() << "branch cutoff = " << vParam[SBVP::BRANCHCUTOFF] << " " << vParam[SBVP::BRANCHMAX] << std::endl;

      BranchMode.set(B_DMCSTAGE, 1); //set BranchModex to main stage
      if (sParam[MIXDMCOPT] == "yes")
      {
        app_log() << "Switching to DMC with fluctuating populations" << std::endl;
        BranchMode.set(B_POPCONTROL, 1); //use standard DMC
        vParam[SBVP::ETRIAL] = vParam[SBVP::EREF];
        app_log() << "  Etrial     = " << vParam[SBVP::ETRIAL] << std::endl;
      }
    }
  }
}

Friends And Related Function Documentation

operator<<

std::ostream& operator<< ( std::ostream &  os, SFNBranch::VParamType &  rhs  )

friend

Definition at line 322 of file SFNBranch.cpp.

{
  for (auto value : rhs)
    os << std::setw(18) << std::setprecision(10) << value;
  return os;
}

Member Data Documentation

branching_cutoff_scheme

std::string branching_cutoff_scheme

private

scheme of branching cutoff

Definition at line 322 of file SFNBranch.h.

Referenced by SFNBranch::initParam(), SFNBranch::registerParameters(), SFNBranch::setBranchCutoff(), and SFNBranch::SFNBranch().

BranchMode

BranchModeType BranchMode

private

Definition at line 300 of file SFNBranch.h.

Referenced by SFNBranch::initParam(), SFNBranch::printStatus(), SFNBranch::SFNBranch(), and SFNBranch::updateParamAfterPopControl().

EtrialUpdateToDoSteps

int EtrialUpdateToDoSteps

private

number of remaning steps in before adjusting ETRIAL, [0, iParam[B_ENERGYUPDATEINTERVAL]]

Definition at line 308 of file SFNBranch.h.

Referenced by SFNBranch::put(), and SFNBranch::updateParamAfterPopControl().

iParam

IParamType iParam

private

Definition at line 302 of file SFNBranch.h.

Referenced by SFNBranch::advanceQMCCounter(), SFNBranch::initParam(), SFNBranch::printStatus(), SFNBranch::put(), SFNBranch::registerParameters(), SFNBranch::regressQMCCounter(), SFNBranch::SFNBranch(), and SFNBranch::updateParamAfterPopControl().

m_param

ParameterSet m_param

private

set of parameters

Definition at line 324 of file SFNBranch.h.

Referenced by SFNBranch::put(), and SFNBranch::registerParameters().

myNode

xmlNodePtr myNode

private

save xml element

Definition at line 310 of file SFNBranch.h.

Referenced by SFNBranch::put().

R2Accepted

accumulator_set<RealType> R2Accepted

private

a simple accumulator for energy

Definition at line 314 of file SFNBranch.h.

Referenced by SFNBranch::initParam(), SFNBranch::SFNBranch(), and SFNBranch::updateParamAfterPopControl().

R2Center

accumulator_set<RealType> R2Center

private

a simple accumulator for reptation's center slice

Definition at line 318 of file SFNBranch.h.

R2Proposed

accumulator_set<RealType> R2Proposed

private

a simple accumulator for energy

Definition at line 316 of file SFNBranch.h.

Referenced by SFNBranch::initParam(), SFNBranch::SFNBranch(), and SFNBranch::updateParamAfterPopControl().

ref_energy_collector

DMCRefEnergy ref_energy_collector

private

collect energy and variance history

Definition at line 312 of file SFNBranch.h.

Referenced by SFNBranch::updateParamAfterPopControl().

sParam

std::vector<std::string> sParam

private

string parameters

Definition at line 326 of file SFNBranch.h.

Referenced by SFNBranch::registerParameters(), SFNBranch::SFNBranch(), and SFNBranch::updateParamAfterPopControl().

vParam

VParamType vParam

private

Definition at line 304 of file SFNBranch.h.

Referenced by SFNBranch::branchWeight(), SFNBranch::branchWeightBare(), SFNBranch::DMCLinkAction(), SFNBranch::getEref(), SFNBranch::getEtrial(), SFNBranch::getTau(), SFNBranch::getTauEff(), SFNBranch::initParam(), SFNBranch::printStatus(), SFNBranch::registerParameters(), SFNBranch::setBranchCutoff(), SFNBranch::SFNBranch(), SFNBranch::symLinkAction(), SFNBranch::symLinkActionBare(), and SFNBranch::updateParamAfterPopControl().

WarmUpToDoSteps

int WarmUpToDoSteps

private

number of remaning steps in warmup, [0, iParam[B_WARMUPSTEPS]]

Definition at line 306 of file SFNBranch.h.

Referenced by SFNBranch::getWarmupToDoSteps(), SFNBranch::put(), and SFNBranch::updateParamAfterPopControl().

---

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

• /home/pk7/projects/qmc/for_cron_doxygen/qmcpack/src/QMCDrivers/SFNBranch.h
• /home/pk7/projects/qmc/for_cron_doxygen/qmcpack/src/QMCDrivers/SFNBranch.cpp