#include <anderson.hpp>

Inheritance diagram for q3::AndersonMixer:

Public Member Functions
	AndersonMixer (Real mixing_parameter=0.7, int history_depth=8)

std::vector< Real >	mix_one_component (const std::vector< Real > &input_density, const std::vector< Real > &output_density) override

std::string	name () const override

void	reset () override

Public Member Functions inherited from q3::RealSpaceMixer
void	initialize (const MixerEnvironment &environment) override
	Supply the representation context the mixer needs before the first mix().

void	mix (const std::vector< std::vector< Real > > &input_density, std::vector< std::vector< Real > > &output_density, int number_of_spin_components) override

	Mixer (Real mixing_parameter, int history_depth)

void	set_global_reduce (std::function< void(std::vector< Real > &)> global_reduce)

void	set_preconditioner (Preconditioner preconditioner)

Public Member Functions inherited from q3::Mixer
	Mixer (Real mixing_parameter, int history_depth)

virtual	~Mixer ()=default

int	history_depth () const

Real	last_residual_norm () const

Real	mixing_parameter () const

Additional Inherited Members
Public Types inherited from q3::RealSpaceMixer
using	Preconditioner = std::function< void(std::vector< Real > &)>

Protected Attributes inherited from q3::RealSpaceMixer
std::function< void(std::vector< Real > &)>	global_reduce_

Preconditioner	preconditioner_

Protected Attributes inherited from q3::Mixer
int	history_depth_

Real	last_residual_norm_ {-1.0}

Real	mixing_parameter_

Detailed Description

Anderson (Pulay) mixing with configurable history depth (real-space). Uses the residual minimization approach for faster SCF convergence.

Definition at line 26 of file anderson.hpp.

Constructor & Destructor Documentation

◆ AndersonMixer()

q3::AndersonMixer::AndersonMixer	(	Real	mixing_parameter = `0.7`,
		int	history_depth = `8`
	)

inlineexplicit

Definition at line 28 of file anderson.hpp.

Member Function Documentation

◆ mix_one_component()

std::vector< Real > q3::AndersonMixer::mix_one_component	(	const std::vector< Real > &	input_density,
		const std::vector< Real > &	output_density
	)

inlineoverridevirtual

Mix one spin component to produce the next input density.

Parameters

input_density	density used to build the potential (rho_in).
output_density	density from diagonalization/sum_band (rho_out).

Returns: mixed density for the next iteration.

Build overlap matrix A[i,j] = <R_i - R_last | R_j - R_last> and RHS b[i] = <R_i - R_last | R_last>

All dot products are accumulated locally first, then reduced together in a single MPI collective call to avoid O(history^2) synchronizations.

Single batched MPI reduction: pack rhs and upper triangle of overlap into one vector, reduce once, then unpack. This is exactly one MPI_Allreduce regardless of history depth.

Implements q3::RealSpaceMixer.

Definition at line 31 of file anderson.hpp.

References q3::lapack::dgels_(), q3::RealSpaceMixer::global_reduce_, q3::Mixer::history_depth_, q3::Mixer::mixing_parameter_, q3::RealSpaceMixer::preconditioner_, and q3::log::warn().

◆ name()

std::string q3::AndersonMixer::name ( ) const

inlineoverridevirtual

Implements q3::Mixer.

Definition at line 207 of file anderson.hpp.

◆ reset()

void q3::AndersonMixer::reset ( )

inlineoverridevirtual

Reimplemented from q3::Mixer.

Definition at line 202 of file anderson.hpp.

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

src/layer_4_computation/iterator/internal/mixing/real_space/anderson.hpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ AndersonMixer()

Member Function Documentation

◆ mix_one_component()

◆ name()

◆ reset()