BigDFT.InputActions module¶
Actions to define on the Input parameters.
This module defines some of the most common actions that a BigDFT user might
like to perform on the input file. Such module therefore sets some of the keys
of the input dictionary to the values needed to perform the operations.
Users might also inspire to the actions performed in order to customize the
runs in a different way. All the functions of this module have as first
argument inp
, the dictionary of the input parameters.
Many other actions are available in BigDFT code. This module only regroups the
most common. Any of these functionalities might be removed from the input file
by the remove()
function.
Note
Any of the action of this module, including the remove()
function,
can be also applied to an instance of the
BigDFT.Inputfiles.Inputfile
class, by removing the first
argument (inp
). This adds extra flexibility as the same method may be
used to a dictionary instance or to a BigDFT input files.
See the example Example.
We now list the available methods, in order of category.
Basic Setup and common functionalities¶

Set the exchange and correlation approximation 

Set the wavelet grid spacing. 

Set the wavelet grid extension by modifying the multiplicative radii. 

Constrain the number of grid points in each direction. 

Optimize the geometry of the system 

Add a collinear spin polarization to the system. 

Charge the system 

Charge the system by removing one electron. Assume that the original 

Set the symmetry detection for the charge density and the ionic forces and stressdef set_symmetry(inp,yes=True): 

Apply an external electric field on the system 

Insert 

Extract a given number of empty states after the scf cycle. 

Define the electronic temperature, in AU ( 

Add an acqueous implicit solvent around the system with the 
Add Grimme's D3 correction to the energy and the forces 
SelfConsistentField setup and algorithms¶

Set the tolerance acceptance level for stopping the selfconsistent iterations. 
Input orbitals are initialized as random coefficients 


Activates the linear scaling mode 

Set the algorithm for scf. 

Method for guessing the kernel at restart. 

Methods for scf of the density kernel. 

Methods for scf of the kernel coefficients. 

Methods for scf of the Support functions. 
InputOutput and restart¶

Set the code to write the orbitals on disk in the provided format 

Read the orbitals from data directory, if available. 
Write the charge density on the disk after the last scf convergence 


Modify the name of the 

Associate the data of the run of a given logfile to the input by retrieving the data directory name of the logfile. 

Write the matrices of the linear scaling formats. 

Writes the 

Dump the support functions. 
PostProcessing and other functionalities¶

Extract the dipole moment from the total charge density. 

Calculate the Partial Density of states. 

Perform a Casida TDDFT coupling matrix extraction. 

Calculate the multipoles on the atoms based on SF. 

Include a cdft constraint into the SCF cycle. 
Setting atomicbased information and other functionalities¶

Insert the atomic positions as a part of the input dictionary 

Employ gpu acceleration when available, for convolutions and Fock operator 

Control the occupation number of the KS orbitals. 

Set the external potential to which the system is submitted outside the QM region 

Employs all the "psppar.*" files of the given directory as pseudopotentials 

Employ the given PSP file for the provided element 

Load a profile or list of profiles. 

Remove action from the input dictionary. 
Note
Each of the actions here must have default value for the arguments
(except the input dictionary inp
). This is needed for a good behaviour
of the function remove.
We list here the extended documentation in alphabetic order.
 add_cdft_constraint(inp, constraint=None, homo_per_fragment={})[source]¶
Include a cdft constraint into the SCF cycle.
Useful for Linear scaling formalism.
 Parameters
constraint (BigDFT.CDFT.CDFTConstraint) – the instantiated constraint
homo_per_fragment (dict) – integer representing the orbital id of the homo of any of the fragments included in the constraint.
 add_empty_scf_orbitals(inp, norbs=10)[source]¶
Insert
norbs
empty orbitals in the scf procedure Parameters
norbs (int) – Number of empty orbitals
Warning
In linear scaling case, this is only meaningful for the direct minimization approach.
 apply_electric_field(inp, elecfield=[0, 0, 0.001])[source]¶
Apply an external electric field on the system
 calculate_dipole(inp)[source]¶
Extract the dipole moment from the total charge density.
Note
This function is useful for the linear scaling setup as the cubic scaling approach always calculates the charge density multipoles.
 calculate_multipoles(inp, yes=True)[source]¶
Calculate the multipoles on the atoms based on SF.
 Parameters
yes (bool) – switch off the calculation if False.
 calculate_pdos(inp)[source]¶
Calculate the Partial Density of states.
Calculate the data needed for Projected DoS on the set of LCAO input wavefunction in the case of the CubicScaling algorithm and onto the Support Functions in the case of the linear scaling.
 calculate_tddft_coupling_matrix(inp, tda=False, rpa=True, fxc=True)[source]¶
Perform a Casida TDDFT coupling matrix extraction.
 Parameters
tda (bool) – when
True
, TammDancoff approximation is used for the extraction of the coupling matrixrpa (bool) – when
False
, the calculation of the RPA term (the linear response of the hartree potential) is switched offfxc (bool) – when
False
, the calculation of the fxc term (the linear response of the XC operator) is switched off.
Note
The arguments
fxc
andrpa
should not be simultaneouslyFalse
.Warning
Presently the LRTDDFT casida fxc is only available for LDA functionals in ABINIT flavour.
 change_data_directory(inp, name='')[source]¶
Modify the name of the
data
directory. Useful to grab the orbitals from another directory than the run name Parameters
name (str) – the name of the run
 charge_and_polarize(inp)[source]¶
 Charge the system by removing one electron. Assume that the original
system is closed shell, thus polarize.
 connect_run_data(inp, log=None)[source]¶
Associate the data of the run of a given logfile to the input by retrieving the data directory name of the logfile.
 Parameters
log (Logfile) – instance of a Logfile class
 extract_virtual_states(inp, nvirt=8, davidson=False, norbv=None, itermax_virt=150)[source]¶
Extract a given number of empty states after the scf cycle.
 optimize_geometry(inp, method='FIRE', nsteps=50, betax=4.0, frac_fluct=1.0, forcemax=0)[source]¶
Optimize the geometry of the system
 Parameters
nsteps (int) – maximum number of atomic steps.
method (str) –
Geometry optimizer. Available keys:
SDCG: A combination of Steepest Descent and Conjugate Gradient
VSSD: Variable Stepsize Steepest Descent method
LBFGS: Limitedmemory BFGS
BFGS: BroydenFletcherGoldfarbShanno
PBFGS: Same as BFGS with an initial Hessian from a force field
DIIS: Direct inversion of iterative subspace
FIRE: Fast Inertial Relaxation Engine, described by Bitzek et al.
SQNM: Stabilized quasiNewton minimzer
betax (float) – the step size for the optimization method. This stepsize is system dependent and it has therefore to be determined for each system.
frac_fluct (float) – Fraction of force fluctuations. Stop if fmax < forces_fluct*frac_fluct.
forcemax (float) – Max forces criterion when stop.
 optimize_kernel(inp, method='DIAG', dynamic_convergence=True, nit=5, rpnrm=1e10, alphamix=0.5)[source]¶
Methods for scf of the density kernel.
Strategies for the optimization of the kernel.
 Parameters
dynamic_convergence (bool) – if False, the threshold for the convergence of the kernel are not dynamically adjusted
nit (int) – number of scf iterations
rpnrm (float) – convergence criterion, change in density/potential
method (str) – optimization method (‘DIRMIN’, ‘DIAG’, ‘NTPOLY’, ‘FOE’)
alphamix (float) – mixing parameter
 optimize_support_functions(inp, nit=1, gnrm=1e06, diis_history=0)[source]¶
Methods for scf of the Support functions.
 read_orbitals_from_disk(inp, mode='cubic')[source]¶
Read the orbitals from data directory, if available.
 Parameters
mode (str) – can be ‘cubic’ or ‘linear’. In the first case, orbitals are read as KS objects, whereas in the second kernel (or coeffs) and support functions are expressed.
 remove(inp, action)[source]¶
Remove action from the input dictionary.
Remove an action from the input file, thereby restoring the default value, as if the action were not specified.
 Parameters
inp (dict) – dictionary to remove the action from.
action (func) – one of the actions of this module. It does not need to be
before (specified) –
effect. (in which case it produces no) –
Example
>>> from Calculators import SystemCalculator as C >>> code=C() >>> inp={} >>> set_xc(inp,'PBE') >>> write_orbitals_on_disk(inp) >>> log=code.run(input=inp) # perform calculations >>> remove(inp, write_orbitals_on_disk) #remove the action >>> read_orbitals_from_disk(inp) >>> # this will restart the scf from the previous orbitals >>> log2=code.run(input=inp)
 set_atomic_positions(inp, posinp=None)[source]¶
Insert the atomic positions as a part of the input dictionary
 set_dispersion_correction(inp)[source]¶
Add Grimme’s D3 correction to the energy and the forces
Warning
Only works with Free Boundary conditions
 set_electronic_temperature(inp, kT=0.001, T=0)[source]¶
Define the electronic temperature, in AU (
kT
) or K (T
)
 set_external_potential(inp, mm_pot)[source]¶
Set the external potential to which the system is submitted outside the QM region
 Parameters
mm_pot (dict) – dictionary of the external potential which contains the information on the counterions
 set_implicit_solvent(inp, itermax=20, minres=0.0001)[source]¶
 Add an acqueous implicit solvent around the system with the
softsphere cavity method
 set_kernel_guess(inp, mode='kernel')[source]¶
Method for guessing the kernel at restart.
 Parameters
mode (str) – Guessing method. Can be: * kernel * coefficients * random * diag * weight * ao * full_kernel * full_coefficients
 set_mesh_sizes(inp, ngrids=64)[source]¶
Constrain the number of grid points in each direction. This is useful when performing periodic system calculations with variable cells which need to be compared each other. In this way the number of degrees of freedom is kept constant throughout the various simuilations.
 set_orbital_occupancy(inp, avg={}, up={}, down={}, kpoint=1)[source]¶
Control the occupation number of the KS orbitals.
With this funtionality one can fix the value of the occupation numbers of the KS orbitals.
 Parameters
avg (dict) – dictionary of the form {i: f} where i is an integer stating the nondefault value of the occupation number, for spin averaged occupancy
up (dict) – same as avg but for the up spin channel
down (dict) – same as avg but for the down spin channel
kpoint (int) – label of the kpoint associated to the occupancy
 set_psp_directory(inp, directory='.')[source]¶
Employs all the “psppar.*” files of the given directory as pseudopotentials
 Parameters
directory (str) – path of the psppar directory
 set_psp_file(inp, filename=None, element=None)[source]¶
Employ the given PSP file for the provided element
 set_rmult(inp, rmult=None, coarse=5.0, fine=8.0)[source]¶
Set the wavelet grid extension by modifying the multiplicative radii.
 Parameters
rmult (float,list) – list of two values that have to be used for the coarse and the fine resolution grid. It may also be a scalar.
coarse (float) – if the argument
rmult
is not provided it sets the coarse radius multiplierfine (float) – if the argument
rmult
is not provided it sets the fine radius multiplier
 set_scf_convergence(inp, gnrm='default', rpnrm='default')[source]¶
Set the tolerance acceptance level for stopping the selfconsistent iterations. Useful both for LS and CS
 set_scf_iterations(inp, nit=[50, 1])[source]¶
Set the number of the iteration per loop
 Parameters
nit (int,list) – integer of the number of iterations. Might be a scalar or a list, up to length two. The first element of the list contains the number of iterations of the direct minimization loop. if
nit
is a scalar, only this contribution is taken into account. The second element is the number of subspace iterations where the hamiltonian is diagonalized in the subspace. For a LS calculation, the number of iteration correspond to the levels of the outer loop.
 set_scf_method(inp, method='dirmin', mixing_on='density', mixing_scheme='Pulay')[source]¶
Set the algorithm for scf.
 Parameters
method (str) – The algoritm chosen. Might be different for the cubic (CS) or linear scaling (LS) algorithm. * dirmin: Direct minimization approach (only CS) * mixing: Mixing scheme (only CS) * hybrid: outer loop of the LS mode * two_levels: two level of accuracy in the scf
mixing_on (str) – May be
"density"
or"potential"
in the"mixing"
case, decide to which quantity the mixing to be performedmixing_scheme (str) –
May be:
Pulay : DIIS mixing on the last 7 iterations
Simple: Simple mixing
Anderson: Anderson scheme
Anderson2: Anderson scheme based on the two pervious iterations
 CG: Conjugate Gradient based on the minimum of the energy with
respect of the potential
Warning
Only the FOE method exhibit asymptotic linear scaling regime.
Todo
Check if the linear scaling case needs another input variable for the mixing of the potential (density)
 set_symmetry(inp, yes=True)[source]¶
Set the symmetry detection for the charge density and the ionic forces and stressdef set_symmetry(inp,yes=True):
 Parameters
yes (bool) – If
False
the symmetry detection is disabled
 set_xc(inp, xc='PBE')[source]¶
Set the exchange and correlation approximation
 Parameters
xc (str) – the Acronym of the XC approximation
Todo
Insert the XC codes corresponding to
libXC
conventions
 spin_polarize(inp, mpol=1)[source]¶
Add a collinear spin polarization to the system.
 Parameters
mpol (int) – spin polarization in Bohr magneton units.
 use_gpu_acceleration(inp)[source]¶
Employ gpu acceleration when available, for convolutions and Fock operator
Todo
Verify what happens when only one of the functionality is enabled at compiletime
 write_cubefiles_around_fermi_level(inp, nplot=1)[source]¶
Writes the
nplot
orbitals around the fermi level in cube format. Parameters
nplot (int) – the number of orbitals to print around the fermi level.
Warning
This would work only for the cubic scaling code at present.
 write_density_on_disk(inp)[source]¶
Write the charge density on the disk after the last scf convergence
 write_orbitals_on_disk(inp, format='binary')[source]¶
Set the code to write the orbitals on disk in the provided format
 Parameters
format (str) – The format to write the orbitals with. Accepts the strings: * ‘binary’ * ‘text’ * ‘etsf’ (requires etsfio enabled)
Todo
Verify if this option works for a linear scaling calulation.
 write_support_function_matrices(inp, format='text')[source]¶
Write the matrices of the linear scaling formats.
 Parameters
format (str) –
The format to write the orbitals with. Accepts the strings:
’binary’
’text’
Todo
Verify if the binary format is available and set the appropriate values
 write_support_functions_on_disk(inp, format='text')[source]¶
Dump the support functions.
Write the support function which are expressed in wavelet basis in the code as files at the end of the calculation.
 Parameters
format (str) – the format of the data, can be ‘text’, ‘ETSF’ or ‘binary’ or one of the allowed codes of the output_wf key.