mpqc::cc::DIISSolver< T > Class Template Reference

Documentation

template<typename T>
class mpqc::cc::DIISSolver< T >

DIISSolver updates the CC T amplitudes using DIIS

Template Parameters

T	the type representing the n-body amplitude set

Public Types
using	Tile = typename T::value_type
using	Policy = typename T::policy_type
using	TVec = TA::DistArrayVector< Tile, Policy >

Public Member Functions
	DIISSolver (const KeyVal &kv)
	The KeyVal constructor. More...
virtual	~DIISSolver ()=default
void	update (std::vector< std::reference_wrapper< T >> &t_pack, const std::vector< std::reference_wrapper< const T >> &r_pack, double dE=0) override
bool	is_converged (double target_precision, double error, double dE) const override
void	reset ()
	Resets the DIIS solver; used when switching to a new solver subspace. More...

Static Public Member Functions
static double	precision_margin_energy ()

Protected Member Functions
virtual void	update_only (std::vector< std::reference_wrapper< T >> &t_pack, const std::vector< std::reference_wrapper< const T >> &r_pack, double dE=0)
TA::DIIS< TVec > &	diis ()

Member Typedef Documentation

Policy

template<typename T >

using mpqc::cc::DIISSolver< T >::Policy = typename T::policy_type

Tile

template<typename T >

using mpqc::cc::DIISSolver< T >::Tile = typename T::value_type

TVec

template<typename T >

using mpqc::cc::DIISSolver< T >::TVec = TA::DistArrayVector<Tile, Policy>

Constructor & Destructor Documentation

DIISSolver()

template<typename T >

mpqc::cc::DIISSolver< T >::DIISSolver ( const KeyVal &  kv )

inline

The KeyVal constructor.

Parameters

kv	the KeyVal object; it will be queried for the following keywords

Keyword	Type	Default	Description
diis_start	int	1	The DIIS extrapolation will begin on the iteration given by this integer.
n_diis	int	8	This specifies maximum number of data sets to retain.
diis_damp	real	0.0	This nonnegative floating point number is used to dampen the DIIS extrapolation.
diis_damping_attenuation	real	1e-3	this nonnegative floating point number defines the 2-norm of the error when when the damping factor for the DIIS extrapolation starts to decay linearly with the error
diis_ngroup	int	1	The number of iterations in a DIIS group. DIIS extrapolation is only used for the first diis_group_nstart of these iterations. If diis_ngroup is 1 and diis_group_nstart is greater than 0, then DIIS will be used on all iterations after and including the start iteration.
diis_group_nstart	int	1	The number of DIIS extrapolations to do at the beginning of an iteration group. See the documentation for diis_ngroup .

~DIISSolver()

template<typename T >

virtual mpqc::cc::DIISSolver< T >::~DIISSolver ( )

virtualdefault

Member Function Documentation

diis()

template<typename T >

TA::DIIS<TVec>& mpqc::cc::DIISSolver< T >::diis ( )

inlineprotected

is_converged()

template<typename T >

bool mpqc::cc::DIISSolver< T >::is_converged ( double  target_precision, double  error, double  dE  ) const

inlineoverride

Tests if the solver has converged

Parameters

target_precision	The desired precision for the final CC energy
error	The value of the error computed from the equation residuals
dE	The energy change between two consecutive solver iterations

Returns

Whether or not the solver has converged

precision_margin_energy()

template<typename T >

static double mpqc::cc::DIISSolver< T >::precision_margin_energy ( )

inlinestatic

Specifies the extra margin for converging energy. DIIS solver is converged to precision eps if the energy between two successive iterations is converged to eps times the margin. Currently it is fixed empirically at 0.1 , i.e. solver is converged if the difference between two consecutive iterations is less than 1/10th of the target precision.

Returns

the extra margin for converging energy

reset()

template<typename T >

void mpqc::cc::DIISSolver< T >::reset ( )

inline

Resets the DIIS solver; used when switching to a new solver subspace.

update()

template<typename T >

void mpqc::cc::DIISSolver< T >::update ( std::vector< std::reference_wrapper< T >> &  t_pack, const std::vector< std::reference_wrapper< const T >> &  r_pack, double  dE = 0  )

inlineoverride

Update the amplitudes using update_only() and extrapolate using DIIS.

Warning

This function assumes that {t1 , t2 } and {r1 , r2 } are congruent, but does not assume any particular structure. Derived classes may impose additional assumptions on the structure of the arguments.

Parameters

t1	the 1-body amplitude set (current values on input, updated values on output)
t2	the 2-body amplitude set (current values on input, updated values on output)
r1	the 1-body amplitude equation residual set (contents may be modified)
r2	the 2-body amplitude equation residual set (contents may be modified)

update_only()

template<typename T >

virtual void mpqc::cc::DIISSolver< T >::update_only ( std::vector< std::reference_wrapper< T >> &  t_pack, const std::vector< std::reference_wrapper< const T >> &  r_pack, double  dE = 0  )

inlineprotectedvirtual

this performs the amplitude update only, to be followed up with DIIS

Warning

This function assumes that {t1 , t2 } and {r1 , r2 } are congruent, but does not assume any particular structure. Derived classes may impose additional assumptions on the structure of the arguments.

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

• mpqc/chemistry/qc/cc/fwd.h
• mpqc/chemistry/qc/cc/solvers.h